diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index d6e08261..4f49e4ee 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -59,8 +59,17 @@ jobs:
         run: yarn test:unit
 
   test-integration:
-    name: Test (Integration)
+    name: Test (Integration) - ${{ matrix.config.name }}
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        config:
+          - name: Default
+            args: --tokenbridge --l3node --l3-token-bridge --l3-fee-token
+            decimals: 18
+          - name: Custom Decimals
+            args: --tokenbridge --l3node --l3-token-bridge --l3-fee-token --l3-fee-token-decimals 12
+            decimals: 12
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -72,7 +81,7 @@ jobs:
         uses: OffchainLabs/actions/run-nitro-test-node@feat-simplify
         with:
           nitro-testnode-ref: release
-          args: --tokenbridge --l3node --l3-token-bridge --l3-fee-token
+          args: ${{ matrix.config.args }}
 
       - name: Copy .env
         run: cp ./.env.example ./.env
@@ -81,4 +90,4 @@ jobs:
         run: yarn build
 
       - name: Test
-        run: yarn test:integration
+        run: DECIMALS=${{decimals}} yarn test:integration
diff --git a/src/createRollup.integration.test.ts b/src/createRollup.integration.test.ts
index 9f30b032..261d0077 100644
--- a/src/createRollup.integration.test.ts
+++ b/src/createRollup.integration.test.ts
@@ -8,6 +8,7 @@ import {
   getInformationFromTestnode,
 } from './testHelpers';
 import { createRollupFetchTransactionHash } from './createRollupFetchTransactionHash';
+import { nativeTokenDecimalsTo18Decimals } from './utils/decimals';
 
 const parentChainPublicClient = createPublicClient({
   chain: nitroTestnodeL2,
@@ -19,6 +20,7 @@ const testnodeAccounts = getNitroTestnodePrivateKeyAccounts();
 const l3TokenBridgeDeployer = testnodeAccounts.l3TokenBridgeDeployer;
 const batchPosters = [testnodeAccounts.deployer.address];
 const validators = [testnodeAccounts.deployer.address];
+const nativeTokenDecimals = Number(process.env.DECIMALS) ?? 18;
 
 describe(`create an AnyTrust chain that uses ETH as gas token`, async () => {
   const { createRollupConfig, createRollupInformation } = await createRollupHelper({
@@ -68,7 +70,7 @@ describe(`create an AnyTrust chain that uses a custom gas token`, async () => {
     client: parentChainPublicClient,
   });
 
-  it(`successfully deploys core contracts through rollup creator (18 decimals)`, async () => {
+  it(`successfully deploys core contracts through rollup creator`, async () => {
     // assert all inputs are correct
     const [arg] = createRollupInformation.transaction.getInputs();
     expect(arg.config).toEqual(createRollupConfig);
@@ -77,7 +79,9 @@ describe(`create an AnyTrust chain that uses a custom gas token`, async () => {
     expect(arg.maxDataSize).toEqual(104_857n);
     expect(arg.nativeToken).toEqual(nativeToken);
     expect(arg.deployFactoriesToL2).toEqual(true);
-    expect(arg.maxFeePerGasForRetryables).toEqual(parseGwei('0.1'));
+    expect(arg.maxFeePerGasForRetryables).toEqual(
+      nativeTokenDecimalsTo18Decimals({ amount: 100n, decimals: nativeTokenDecimals }),
+    );
 
     // assert the transaction executed successfully
     expect(createRollupInformation.transactionReceipt.status).toEqual('success');
diff --git a/src/createRollup.ts b/src/createRollup.ts
index 4a0cbc27..0112c2e3 100644
--- a/src/createRollup.ts
+++ b/src/createRollup.ts
@@ -15,6 +15,8 @@ import {
 } from './createRollupPrepareTransaction';
 import { CreateRollupParams } from './types/createRollupTypes';
 import { validateParentChain } from './types/ParentChain';
+import { getNativeTokenDecimals, nativeTokenDecimalsTo18Decimals } from './utils/decimals';
+import { defaults as createRollupDefaults } from './createRollupDefaults';
 
 type EnsureCustomGasTokenAllowanceGrantedToRollupCreatorParams<TChain extends Chain | undefined> = {
   nativeToken: Address;
@@ -170,9 +172,21 @@ export async function createRollup<TChain extends Chain | undefined>({
     });
   }
 
+  const decimals = await getNativeTokenDecimals({
+    publicClient: parentChainPublicClient,
+    nativeTokenAddress: nativeToken ?? zeroAddress,
+  });
+  const maxFeePerGas = nativeTokenDecimalsTo18Decimals({
+    amount: params.maxFeePerGasForRetryables ?? createRollupDefaults.maxFeePerGasForRetryables,
+    decimals,
+  });
+
   // prepare the transaction for deploying the core contracts
   const txRequest = await createRollupPrepareTransactionRequest({
-    params,
+    params: {
+      ...params,
+      maxFeePerGasForRetryables: maxFeePerGas,
+    },
     account: account.address,
     publicClient: parentChainPublicClient,
   });
diff --git a/src/createRollupGetRetryablesFees.ts b/src/createRollupGetRetryablesFees.ts
index 53d6fb9a..4b73e562 100644
--- a/src/createRollupGetRetryablesFees.ts
+++ b/src/createRollupGetRetryablesFees.ts
@@ -7,7 +7,6 @@ import {
   EstimateGasParameters,
   encodeFunctionData,
   decodeFunctionResult,
-  zeroAddress,
 } from 'viem';
 
 import { rollupCreatorABI } from './contracts/RollupCreator';
@@ -16,7 +15,6 @@ import { isCustomFeeTokenAddress } from './utils/isCustomFeeTokenAddress';
 import { defaults as createRollupDefaults } from './createRollupDefaults';
 import { applyPercentIncrease } from './utils/gasOverrides';
 import { createRollupDefaultRetryablesFees } from './constants';
-import { getNativeTokenDecimals, scaleToNativeTokenDecimals } from './utils/decimals';
 
 const deployHelperABI = [
   {
@@ -102,14 +100,7 @@ export async function createRollupGetRetryablesFees<TChain extends Chain | undef
   const isCustomGasToken = isCustomFeeTokenAddress(nativeToken);
 
   const inbox = isCustomGasToken ? erc20TemplateInbox : ethTemplateInbox;
-  const decimals = await getNativeTokenDecimals({
-    publicClient,
-    nativeTokenAddress: nativeToken ?? zeroAddress,
-  });
-  const maxFeePerGas = scaleToNativeTokenDecimals({
-    amount: maxFeePerGasForRetryables ?? createRollupDefaults.maxFeePerGasForRetryables,
-    decimals,
-  });
+  const maxFeePerGas = maxFeePerGasForRetryables ?? createRollupDefaults.maxFeePerGasForRetryables;
 
   const baseFeeWithBuffer = applyPercentIncrease({
     base: await publicClient.getGasPrice(),
diff --git a/src/createTokenBridge.integration.test.ts b/src/createTokenBridge.integration.test.ts
index 704923a5..c40fcd3e 100644
--- a/src/createTokenBridge.integration.test.ts
+++ b/src/createTokenBridge.integration.test.ts
@@ -20,6 +20,7 @@ import { createTokenBridgePrepareSetWethGatewayTransactionRequest } from './crea
 import { createTokenBridgePrepareSetWethGatewayTransactionReceipt } from './createTokenBridgePrepareSetWethGatewayTransactionReceipt';
 import { createTokenBridge } from './createTokenBridge';
 import { TokenBridgeContracts } from './types/TokenBridgeContracts';
+import { scaleToNativeTokenDecimals } from './utils/decimals';
 
 const testnodeAccounts = getNitroTestnodePrivateKeyAccounts();
 const l2RollupOwner = testnodeAccounts.l2RollupOwner;
@@ -104,6 +105,8 @@ async function checkWethGateways(
   expect(tokenBridgeContracts.orbitChainContracts.wethGateway).not.toEqual(zeroAddress);
 }
 
+const nativeTokenDecimals = Number(process.env.DECIMALS) ?? 18;
+
 describe('createTokenBridge utils function', () => {
   it(`successfully deploys token bridge contracts through token bridge creator`, async () => {
     const testnodeInformation = getInformationFromTestnode();
@@ -218,7 +221,10 @@ describe('createTokenBridge utils function', () => {
       data: encodeFunctionData({
         abi: erc20ABI,
         functionName: 'transfer',
-        args: [l3RollupOwner.address, parseEther('500')],
+        args: [
+          l3RollupOwner.address,
+          scaleToNativeTokenDecimals({ amount: 500n, decimals: nativeTokenDecimals }),
+        ],
       }),
       value: BigInt(0),
       account: l3TokenBridgeDeployer,
@@ -368,7 +374,7 @@ describe('createTokenBridge', () => {
     checkWethGateways(tokenBridgeContracts, { customFeeToken: false });
   });
 
-  it('successfully deploys token bridge contracts with a custom fee token (18 decimals)', async () => {
+  it('successfully deploys token bridge contracts with a custom fee token', async () => {
     const testnodeInformation = getInformationFromTestnode();
 
     // deploy a fresh token bridge creator, because it is only possible to deploy one token bridge per rollup per token bridge creator
@@ -384,7 +390,10 @@ describe('createTokenBridge', () => {
       data: encodeFunctionData({
         abi: erc20ABI,
         functionName: 'transfer',
-        args: [l3RollupOwner.address, parseEther('500')],
+        args: [
+          l3RollupOwner.address,
+          scaleToNativeTokenDecimals({ amount: 500n, decimals: nativeTokenDecimals }),
+        ],
       }),
       value: BigInt(0),
       account: l3TokenBridgeDeployer,
@@ -437,10 +446,6 @@ describe('createTokenBridge', () => {
     checkWethGateways(tokenBridgeContracts, { customFeeToken: true });
   });
 
-  it('successfully deploys token bridge contracts with a custom fee token (non-18 decimals)', async () => {
-    // Deploy a custom chain with non-18 decimals
-  });
-
   it('should throw when createTokenBridge is called multiple times', async () => {
     const testnodeInformation = getInformationFromTestnode();