input: add production taproot witness types for final channels

diff --git a/input/size.go b/input/size.go
index f1c56ff..e88a934 100644
--- a/input/size.go
+++ b/input/size.go
@@ -275,18 +275,30 @@ const (
 	HtlcTimeoutWeight = 663
 
 	// TaprootHtlcTimeoutWeight is the total weight of the taproot HTLC
-	// timeout transaction.
+	// timeout transaction (using staging scripts).
 	TaprootHtlcTimeoutWeight = 645
 
+	// TaprootHtlcTimeoutWeightFinal is the total weight of the taproot HTLC
+	// timeout transaction using production scripts (with OP_CHECKSIGVERIFY
+	// instead of OP_CHECKSIG + OP_DROP). This is not referenced at runtime
+	// because taproot channels use zero-fee HTLC transactions.
+	TaprootHtlcTimeoutWeightFinal = 641
+
 	// HtlcSuccessWeight 703 weight
 	// HtlcSuccessWeight is the weight of the HTLC success transaction
 	// which will transition an incoming HTLC to the delay-and-claim state.
 	HtlcSuccessWeight = 703
 
 	// TaprootHtlcSuccessWeight is the total weight of the taproot HTLC
-	// success transaction.
+	// success transaction (using staging scripts).
 	TaprootHtlcSuccessWeight = 705
 
+	// TaprootHtlcSuccessWeightFinal is the total weight of the taproot HTLC
+	// success transaction using production scripts (with OP_CHECKSIGVERIFY
+	// instead of OP_CHECKSIG + OP_DROP). This is not referenced at runtime
+	// because taproot channels use zero-fee HTLC transactions.
+	TaprootHtlcSuccessWeightFinal = 701
+
 	// HtlcConfirmedScriptOverhead 3 bytes
 	// HtlcConfirmedScriptOverhead is the extra length of an HTLC script
 	// that requires confirmation before it can be spent. These extra bytes
@@ -625,6 +637,16 @@ const (
 	TaprootToLocalWitnessSize = 1 + 1 + 65 + 1 + TaprootToLocalScriptSize +
 		1 + TaprootBaseControlBlockWitnessSize + 32
 
+	// TaprootToLocalScriptSizeFinal: 40 bytes (production scripts).
+	// Replaces OP_CHECKSIG + OP_CSV + OP_DROP with
+	// OP_CHECKSIGVERIFY + OP_CSV, saving 1 byte.
+	TaprootToLocalScriptSizeFinal = TaprootToLocalScriptSize - 1
+
+	// TaprootToLocalWitnessSizeFinal: 174 bytes (production scripts).
+	TaprootToLocalWitnessSizeFinal = 1 + 1 + 65 + 1 +
+		TaprootToLocalScriptSizeFinal +
+		1 + TaprootBaseControlBlockWitnessSize + 32
+
 	// TaprootToLocalRevokeScriptSize: 68 bytes
 	//	- OP_DATA: 1 byte
 	//	- local key: 32 bytes
@@ -667,6 +689,16 @@ const (
 		TaprootToRemoteScriptSize + 1 +
 		TaprootBaseControlBlockWitnessSize)
 
+	// TaprootToRemoteScriptSizeFinal: 36 bytes (production scripts).
+	// Replaces OP_CHECKSIG + OP_1 + OP_CSV + OP_DROP with
+	// OP_CHECKSIGVERIFY + OP_1 + OP_CSV, saving 1 byte.
+	TaprootToRemoteScriptSizeFinal = TaprootToRemoteScriptSize - 1
+
+	// TaprootToRemoteWitnessSizeFinal: 138 bytes (production scripts).
+	TaprootToRemoteWitnessSizeFinal = (1 + 1 + 65 + 1 +
+		TaprootToRemoteScriptSizeFinal + 1 +
+		TaprootBaseControlBlockWitnessSize)
+
 	// TaprootAnchorWitnessSize: 67 bytes
 	//
 	// In this case, we use the custom sighash size to give the most
@@ -695,6 +727,17 @@ const (
 		TaprootSecondLevelHtlcScriptSize + 1 +
 		TaprootBaseControlBlockWitnessSize
 
+	// TaprootSecondLevelHtlcScriptSizeFinal: 40 bytes (production
+	// scripts). Replaces OP_CHECKSIG + OP_DROP with OP_CHECKSIGVERIFY,
+	// saving 1 byte.
+	//nolint:ll
+	TaprootSecondLevelHtlcScriptSizeFinal = TaprootSecondLevelHtlcScriptSize - 1
+
+	// TaprootSecondLevelHtlcWitnessSizeFinal: production scripts.
+	TaprootSecondLevelHtlcWitnessSizeFinal = 1 + 1 + 65 + 1 +
+		TaprootSecondLevelHtlcScriptSizeFinal + 1 +
+		TaprootBaseControlBlockWitnessSize
+
 	// TaprootSecondLevelRevokeWitnessSize
 	//      - number_of_witness_elements: 1 byte
 	//      - sig_len: 1 byte
@@ -729,6 +772,13 @@ const (
 	TaprootHtlcOfferedRemoteTimeoutScriptSize = (1 + 32 + 1 + 1 + 1 + 1 +
 		1 + 4 + 1 + 1)
 
+	// TaprootHtlcOfferedRemoteTimeoutScriptSizeFinal: 43 bytes
+	// (production scripts). Replaces OP_CHECKSIG with OP_CHECKSIGVERIFY
+	// (saves 1 byte by dropping the trailing OP_DROP), but
+	// OP_CHECKSEQUENCEVERIFY + OP_DROP becomes CSV + OP_VERIFY (same
+	// size). Net saving: 1 byte.
+	TaprootHtlcOfferedRemoteTimeoutScriptSizeFinal = TaprootHtlcOfferedRemoteTimeoutScriptSize - 1 //nolint:ll
+
 	// TaprootHtlcOfferedRemoteTimeoutwitSize: 176 bytes
 	//      - number_of_witness_elements: 1 byte
 	//      - sig_len: 1 byte
@@ -742,6 +792,11 @@ const (
 		TaprootHtlcOfferedRemoteTimeoutScriptSize + 1 +
 		TaprootBaseControlBlockWitnessSize + 32
 
+	// TaprootHtlcOfferedRemoteTimeoutWitnessSizeFinal: 174 bytes (production scripts)
+	TaprootHtlcOfferedRemoteTimeoutWitnessSizeFinal = 1 + 1 + 65 + 1 +
+		TaprootHtlcOfferedRemoteTimeoutScriptSizeFinal + 1 +
+		TaprootBaseControlBlockWitnessSize + 32
+
 	// TaprootHtlcOfferedLocalTmeoutScriptSize:
 	//	- OP_DATA: 1 byte (pub key len)
 	//	- local_key: 32 bytes
@@ -751,6 +806,12 @@ const (
 	//	- OP_CHECKSIG: 1 byte
 	TaprootHtlcOfferedLocalTimeoutScriptSize = 1 + 32 + 1 + 1 + 32 + 1
 
+	// TaprootHtlcOfferedLocalTimeoutScriptSizeFinal is the same as the
+	// staging version since SenderHTLCTapLeafTimeout ignores script
+	// options (the script is already identical between staging and
+	// production).
+	TaprootHtlcOfferedLocalTimeoutScriptSizeFinal = TaprootHtlcOfferedLocalTimeoutScriptSize //nolint:ll
+
 	// TaprootOfferedLocalTimeoutWitnessSize
 	//      - number_of_witness_elements: 1 byte
 	//      - sig_len: 1 byte
@@ -766,6 +827,15 @@ const (
 		TaprootHtlcOfferedLocalTimeoutScriptSize + 1 +
 		TaprootBaseControlBlockWitnessSize + 32
 
+	// TaprootOfferedLocalTimeoutWitnessSizeFinal: 235 bytes
+	// (production scripts). Not currently referenced because there is no
+	// dedicated Final witness type for this spending path — the script is
+	// identical between staging and final as SenderHTLCTapLeafTimeout
+	// ignores script options.
+	TaprootOfferedLocalTimeoutWitnessSizeFinal = 1 + 1 + 65 + 1 + 65 + 1 +
+		TaprootHtlcOfferedLocalTimeoutScriptSizeFinal + 1 +
+		TaprootBaseControlBlockWitnessSize + 32
+
 	// TaprootHtlcAcceptedRemoteSuccessScriptSize:
 	//      - OP_SIZE: 1 byte
 	//      - OP_DATA: 1 byte
@@ -784,6 +854,11 @@ const (
 	TaprootHtlcAcceptedRemoteSuccessScriptSize = 1 + 1 + 1 + 1 + 1 + 1 +
 		1 + 20 + 1 + 32 + 1 + 1 + 1 + 1
 
+	// TaprootHtlcAcceptedRemoteSuccessScriptSizeFinal: 43 bytes
+	// (production scripts). Replaces OP_CHECKSIG + OP_CSV + OP_DROP with
+	// OP_CHECKSIGVERIFY + OP_CSV, saving 1 byte (the trailing OP_DROP).
+	TaprootHtlcAcceptedRemoteSuccessScriptSizeFinal = TaprootHtlcAcceptedRemoteSuccessScriptSize - 1 //nolint:ll
+
 	// TaprootHtlcAcceptedRemoteSuccessScriptSize:
 	//      - number_of_witness_elements: 1 byte
 	//      - sig_len: 1 byte
@@ -799,6 +874,13 @@ const (
 		TaprootHtlcAcceptedRemoteSuccessScriptSize + 1 +
 		TaprootBaseControlBlockWitnessSize + 32
 
+	// TaprootHtlcAcceptedRemoteSuccessWitnessSizeFinal: 166 bytes
+	// (production scripts).
+	TaprootHtlcAcceptedRemoteSuccessWitnessSizeFinal = 1 + 1 + 65 +
+		1 + 32 + 1 +
+		TaprootHtlcAcceptedRemoteSuccessScriptSizeFinal + 1 +
+		TaprootBaseControlBlockWitnessSize + 32
+
 	// TaprootHtlcAcceptedLocalSuccessScriptSize:
 	//      - OP_SIZE: 1 byte
 	//      - OP_DATA: 1 byte
@@ -817,6 +899,12 @@ const (
 	TaprootHtlcAcceptedLocalSuccessScriptSize = 1 + 1 + 1 + 1 + 1 + 1 +
 		20 + 1 + 1 + 32 + 1 + 1 + 32 + 1
 
+	// TaprootHtlcAcceptedLocalSuccessScriptSizeFinal is the same as the
+	// staging version since ReceiverHtlcTapLeafSuccess ignores script
+	// options (the script is already identical between staging and
+	// production).
+	TaprootHtlcAcceptedLocalSuccessScriptSizeFinal = TaprootHtlcAcceptedLocalSuccessScriptSize //nolint:ll
+
 	// TaprootHtlcAcceptedLocalSuccessWitnessSize:
 	//      - number_of_witness_elements: 1 byte
 	//      - sig_len: 1 byte
@@ -833,6 +921,16 @@ const (
 	TaprootHtlcAcceptedLocalSuccessWitnessSize = 1 + 1 + 65 + 1 + 65 + 1 +
 		32 + 1 + TaprootHtlcAcceptedLocalSuccessScriptSize + 1 +
 		TaprootBaseControlBlockWitnessSize + 32
+
+	// TaprootHtlcAcceptedLocalSuccessWitnessSizeFinal: 271
+	// bytes (production scripts). Not currently referenced because there
+	// is no dedicated Final witness type for this spending path — the
+	// script is identical between staging and final as
+	// ReceiverHtlcTapLeafSuccess ignores script options.
+	TaprootHtlcAcceptedLocalSuccessWitnessSizeFinal = 1 + 1 +
+		65 + 1 + 65 + 1 + 32 + 1 +
+		TaprootHtlcAcceptedLocalSuccessScriptSizeFinal + 1 +
+		TaprootBaseControlBlockWitnessSize + 32
 )
 
 // EstimateCommitTxWeight estimate commitment transaction weight depending on
diff --git a/input/size_test.go b/input/size_test.go
index 2fba2c7..2e80515 100644
--- a/input/size_test.go
+++ b/input/size_test.go
@@ -1019,6 +1019,49 @@ var witnessSizeTests = []witnessSizeTest{
 			return witness
 		},
 	},
+	{
+		name:    "taproot second level htlc success+timeout final",
+		expSize: input.TaprootSecondLevelHtlcWitnessSizeFinal,
+		genWitness: func(t *testing.T) wire.TxWitness {
+			testKey, err := btcec.NewPrivateKey()
+			require.NoError(t, err)
+
+			signer := &dummySigner{}
+
+			scriptTree, err := input.SecondLevelHtlcTapscriptTree(
+				testKey.PubKey(), testCSVDelay,
+				input.NoneTapLeaf(),
+				input.WithProdScripts(),
+			)
+			require.NoError(t, err)
+
+			tapScriptRoot := scriptTree.RootNode.TapHash()
+
+			revokeKey, err := btcec.NewPrivateKey()
+			require.NoError(t, err)
+
+			tapLeaf := scriptTree.LeafMerkleProofs[0].TapLeaf
+			witnessScript := tapLeaf.Script
+			signDesc := &input.SignDescriptor{
+				KeyDesc: keychain.KeyDescriptor{
+					PubKey: revokeKey.PubKey(),
+				},
+				WitnessScript: witnessScript,
+				HashType:      txscript.SigHashAll,
+				InputIndex:    0,
+				SignMethod:    input.TaprootKeySpendSignMethod,
+				TapTweak:      tapScriptRoot[:],
+			}
+
+			witness, err := input.TaprootHtlcSpendSuccess(
+				signer, signDesc, testTx, revokeKey.PubKey(),
+				scriptTree,
+			)
+			require.NoError(t, err)
+
+			return witness
+		},
+	},
 	{
 		name:    "taproot second level htlc revoke",
 		expSize: input.TaprootSecondLevelRevokeWitnessSize,
@@ -1353,6 +1396,76 @@ var witnessSizeTests = []witnessSizeTest{
 			)
 			require.NoError(t, err)
 
+			return witness
+		},
+	},
+	// Production taproot (Final) variants. These use WithProdScripts()
+	// which replaces OP_CHECKSIG + OP_DROP with OP_CHECKSIGVERIFY in
+	// the remote timeout and remote success scripts.
+	{
+		name:    "taproot to local sweep final",
+		expSize: input.TaprootToLocalWitnessSizeFinal,
+		genWitness: func(t *testing.T) wire.TxWitness {
+			testKey, err := btcec.NewPrivateKey()
+			require.NoError(t, err)
+
+			signer := &dummySigner{}
+			commitScriptTree, err := input.NewLocalCommitScriptTree(
+				testCSVDelay, testKey.PubKey(),
+				testKey.PubKey(), input.NoneTapLeaf(),
+				input.WithProdScripts(),
+			)
+			require.NoError(t, err)
+
+			signDesc := &input.SignDescriptor{
+				KeyDesc: keychain.KeyDescriptor{
+					PubKey: testKey.PubKey(),
+				},
+				WitnessScript: commitScriptTree.SettleLeaf.Script,
+				HashType:      txscript.SigHashAll,
+				InputIndex:    0,
+				SignMethod:    input.TaprootScriptSpendSignMethod,
+			}
+
+			witness, err := input.TaprootCommitSpendSuccess(
+				signer, signDesc, testTx,
+				commitScriptTree.TapscriptTree,
+			)
+			require.NoError(t, err)
+
+			return witness
+		},
+	},
+	{
+		name:    "taproot to remote sweep final",
+		expSize: input.TaprootToRemoteWitnessSizeFinal,
+		genWitness: func(t *testing.T) wire.TxWitness {
+			testKey, err := btcec.NewPrivateKey()
+			require.NoError(t, err)
+
+			signer := &dummySigner{}
+			commitScriptTree, err := input.NewRemoteCommitScriptTree(
+				testKey.PubKey(), input.NoneTapLeaf(),
+				input.WithProdScripts(),
+			)
+			require.NoError(t, err)
+
+			signDesc := &input.SignDescriptor{
+				KeyDesc: keychain.KeyDescriptor{
+					PubKey: testKey.PubKey(),
+				},
+				WitnessScript: commitScriptTree.SettleLeaf.Script,
+				HashType:      txscript.SigHashAll,
+				InputIndex:    0,
+				SignMethod:    input.TaprootScriptSpendSignMethod,
+			}
+
+			witness, err := input.TaprootCommitRemoteSpend(
+				signer, signDesc, testTx,
+				commitScriptTree.TapscriptTree,
+			)
+			require.NoError(t, err)
+
 			return witness
 		},
 	},
diff --git a/input/witnessgen.go b/input/witnessgen.go
index c49328a..aa23493 100644
--- a/input/witnessgen.go
+++ b/input/witnessgen.go
@@ -255,6 +255,41 @@ const (
 	// settled output of a malicious counterparty's who broadcasts a
 	// revoked taproot commitment transaction.
 	TaprootCommitmentRevoke StandardWitnessType = 34
+
+	// TaprootLocalCommitSpendFinal is a witness type that allows us to spend
+	// our settled local commitment after a CSV delay when we force close
+	// a final taproot channel (using production scripts).
+	TaprootLocalCommitSpendFinal StandardWitnessType = 35
+
+	// TaprootRemoteCommitSpendFinal is a witness type that allows us to spend
+	// our settled remote commitment after a CSV delay when the remote party
+	// has force closed a final taproot channel (using production scripts).
+	TaprootRemoteCommitSpendFinal StandardWitnessType = 36
+
+	// TaprootHtlcOfferedTimeoutSecondLevelFinal is a witness that allows us to
+	// timeout an HTLC we offered to the remote party on our commitment
+	// transaction for final taproot channels (using production scripts).
+	TaprootHtlcOfferedTimeoutSecondLevelFinal StandardWitnessType = 37
+
+	// TaprootHtlcAcceptedSuccessSecondLevelFinal is a witness that allows us to
+	// sweep an HTLC we accepted on our commitment transaction after we go
+	// to the second level on chain for final taproot channels (using production scripts).
+	TaprootHtlcAcceptedSuccessSecondLevelFinal StandardWitnessType = 38
+
+	// TaprootHtlcOfferedRemoteTimeoutFinal is a witness that allows us to sweep
+	// an HTLC we offered to the remote party that lies on the commitment
+	// transaction for the remote party for final taproot channels (using production scripts).
+	TaprootHtlcOfferedRemoteTimeoutFinal StandardWitnessType = 39
+
+	// TaprootHtlcAcceptedRemoteSuccessFinal is a witness that allows us to
+	// sweep an HTLC that was offered to us by the remote party for final
+	// taproot channels (using production scripts).
+	TaprootHtlcAcceptedRemoteSuccessFinal StandardWitnessType = 40
+
+	// TaprootCommitmentRevokeFinal is a witness that allows us to sweep the
+	// settled output of a malicious counterparty's who broadcasts a
+	// revoked final taproot commitment transaction (using production scripts).
+	TaprootCommitmentRevokeFinal StandardWitnessType = 41
 )
 
 // String returns a human readable version of the target WitnessType.
@@ -367,6 +402,27 @@ func (wt StandardWitnessType) String() string {
 	case TaprootCommitmentRevoke:
 		return "TaprootCommitmentRevoke"
 
+	case TaprootLocalCommitSpendFinal:
+		return "TaprootLocalCommitSpendFinal"
+
+	case TaprootRemoteCommitSpendFinal:
+		return "TaprootRemoteCommitSpendFinal"
+
+	case TaprootHtlcOfferedTimeoutSecondLevelFinal:
+		return "TaprootHtlcOfferedTimeoutSecondLevelFinal"
+
+	case TaprootHtlcAcceptedSuccessSecondLevelFinal:
+		return "TaprootHtlcAcceptedSuccessSecondLevelFinal"
+
+	case TaprootHtlcOfferedRemoteTimeoutFinal:
+		return "TaprootHtlcOfferedRemoteTimeoutFinal"
+
+	case TaprootHtlcAcceptedRemoteSuccessFinal:
+		return "TaprootHtlcAcceptedRemoteSuccessFinal"
+
+	case TaprootCommitmentRevokeFinal:
+		return "TaprootCommitmentRevokeFinal"
+
 	default:
 		return fmt.Sprintf("Unknown WitnessType: %v", uint32(wt))
 	}
@@ -516,9 +572,16 @@ func (wt StandardWitnessType) WitnessGenerator(signer Signer,
 		case NestedWitnessKeyHash:
 			return signer.ComputeInputScript(tx, desc)
 
-		case TaprootLocalCommitSpend:
-			// Ensure that the sign desc has the proper sign method
-			// set, and a valid prev output fetcher.
+		case TaprootLocalCommitSpend, TaprootLocalCommitSpendFinal:
+			// Production (Final) taproot witness types share the
+			// same generation logic as their staging counterparts.
+			// The script differences between staging and final
+			// are captured in the SignDescriptor's script tree
+			// (ControlBlock, TapLeaf, etc.) at commitment
+			// construction time, so the witness generator here
+			// simply signs against whatever scripts were
+			// pre-populated — no channel-type awareness is needed
+			// at this layer.
 			desc.SignMethod = TaprootScriptSpendSignMethod
 
 			// The control block bytes must be set at this point.
@@ -538,7 +601,7 @@ func (wt StandardWitnessType) WitnessGenerator(signer Signer,
 				Witness: witness,
 			}, nil
 
-		case TaprootRemoteCommitSpend:
+		case TaprootRemoteCommitSpend, TaprootRemoteCommitSpendFinal:
 			// Ensure that the sign desc has the proper sign method
 			// set, and a valid prev output fetcher.
 			desc.SignMethod = TaprootScriptSpendSignMethod
@@ -583,7 +646,9 @@ func (wt StandardWitnessType) WitnessGenerator(signer Signer,
 			}, nil
 
 		case TaprootHtlcOfferedTimeoutSecondLevel,
-			TaprootHtlcAcceptedSuccessSecondLevel:
+			TaprootHtlcAcceptedSuccessSecondLevel,
+			TaprootHtlcOfferedTimeoutSecondLevelFinal,
+			TaprootHtlcAcceptedSuccessSecondLevelFinal:
 			// Ensure that the sign desc has the proper sign method
 			// set, and a valid prev output fetcher.
 			desc.SignMethod = TaprootScriptSpendSignMethod
@@ -671,7 +736,8 @@ func (wt StandardWitnessType) WitnessGenerator(signer Signer,
 				Witness: witness,
 			}, nil
 
-		case TaprootHtlcOfferedRemoteTimeout:
+		case TaprootHtlcOfferedRemoteTimeout,
+			TaprootHtlcOfferedRemoteTimeoutFinal:
 			// Ensure that the sign desc has the proper sign method
 			// set, and a valid prev output fetcher.
 			desc.SignMethod = TaprootScriptSpendSignMethod
@@ -693,7 +759,7 @@ func (wt StandardWitnessType) WitnessGenerator(signer Signer,
 				Witness: witness,
 			}, nil
 
-		case TaprootCommitmentRevoke:
+		case TaprootCommitmentRevoke, TaprootCommitmentRevokeFinal:
 			// Ensure that the sign desc has the proper sign method
 			// set, and a valid prev output fetcher.
 			desc.SignMethod = TaprootScriptSpendSignMethod
@@ -715,6 +781,26 @@ func (wt StandardWitnessType) WitnessGenerator(signer Signer,
 				Witness: witness,
 			}, nil
 
+		case TaprootHtlcAcceptedRemoteSuccess,
+			TaprootHtlcAcceptedRemoteSuccessFinal:
+			desc.SignMethod = TaprootScriptSpendSignMethod
+
+			if desc.ControlBlock == nil {
+				return nil, fmt.Errorf("control block " +
+					"must be set for taproot spend")
+			}
+
+			witness, err := SenderHTLCScriptTaprootRedeem(
+				signer, desc, tx, nil, nil, nil,
+			)
+			if err != nil {
+				return nil, err
+			}
+
+			return &Script{
+				Witness: witness,
+			}, nil
+
 		default:
 			return nil, fmt.Errorf("unknown witness type: %v", wt)
 		}
@@ -832,11 +918,17 @@ func (wt StandardWitnessType) SizeUpperBound() (lntypes.WeightUnit,
 	case TaprootLocalCommitSpend:
 		return TaprootToLocalWitnessSize, false, nil
 
-	// Sweeping a self output after the remote party fro ce closes. Must
+	case TaprootLocalCommitSpendFinal:
+		return TaprootToLocalWitnessSizeFinal, false, nil
+
+	// Sweeping a self output after the remote party force closes. Must
 	// wait 1 CSV.
 	case TaprootRemoteCommitSpend:
 		return TaprootToRemoteWitnessSize, false, nil
 
+	case TaprootRemoteCommitSpendFinal:
+		return TaprootToRemoteWitnessSizeFinal, false, nil
+
 	// Sweeping our anchor output with a key spend witness.
 	case TaprootAnchorSweepSpend:
 		return TaprootAnchorWitnessSize, false, nil
@@ -846,6 +938,11 @@ func (wt StandardWitnessType) SizeUpperBound() (lntypes.WeightUnit,
 
 		return TaprootSecondLevelHtlcWitnessSize, false, nil
 
+	case TaprootHtlcOfferedTimeoutSecondLevelFinal,
+		TaprootHtlcAcceptedSuccessSecondLevelFinal:
+
+		return TaprootSecondLevelHtlcWitnessSizeFinal, false, nil
+
 	case TaprootHtlcSecondLevelRevoke:
 		return TaprootSecondLevelRevokeWitnessSize, false, nil
 
@@ -858,16 +955,24 @@ func (wt StandardWitnessType) SizeUpperBound() (lntypes.WeightUnit,
 	case TaprootHtlcOfferedRemoteTimeout:
 		return TaprootHtlcOfferedRemoteTimeoutWitnessSize, false, nil
 
+	case TaprootHtlcOfferedRemoteTimeoutFinal:
+		return TaprootHtlcOfferedRemoteTimeoutWitnessSizeFinal, false,
+			nil
+
 	case TaprootHtlcLocalOfferedTimeout:
 		return TaprootOfferedLocalTimeoutWitnessSize, false, nil
 
 	case TaprootHtlcAcceptedRemoteSuccess:
 		return TaprootHtlcAcceptedRemoteSuccessWitnessSize, false, nil
 
+	case TaprootHtlcAcceptedRemoteSuccessFinal:
+		return TaprootHtlcAcceptedRemoteSuccessWitnessSizeFinal, false,
+			nil
+
 	case TaprootHtlcAcceptedLocalSuccess:
 		return TaprootHtlcAcceptedLocalSuccessWitnessSize, false, nil
 
-	case TaprootCommitmentRevoke:
+	case TaprootCommitmentRevoke, TaprootCommitmentRevokeFinal:
 		return TaprootToLocalRevokeWitnessSize, false, nil
 	}