diff --git a/sdk/scripts/postbuild.js b/sdk/scripts/postbuild.js
index c632f74a7..0e2314dd5 100644
--- a/sdk/scripts/postbuild.js
+++ b/sdk/scripts/postbuild.js
@@ -20,52 +20,75 @@ environments.forEach((environment) => {
 	console.log(``);
 
 	isomorphicPackages.forEach((package) => {
-		const isomorphPath = path.join(
+
+		// We want to overwrite the base isomorphic files (the "target" files) with the concrete implementation code and definition files (the "source" files).
+
+		const isomorphicFolderPath = path.join(
 			__dirname,
 			'..',
 			'lib',
 			environment,
-			'isomorphic',
-			package + '.js'
+			'isomorphic'
 		);
 
 		const targetEnv = forceEnv ? forceEnv : environment;
 
-		const targetPath = path.join(
-			__dirname,
-			'..',
-			'lib',
-			environment,
-			'isomorphic',
-			`${package}.${targetEnv}.js`
-		);
+		const filesToSwap = [
+			{
+				source: `${package}.${targetEnv}.js`,
+				target: `${package}.js`,
+			},
+			{
+				source: `${package}.${targetEnv}.d.ts`,
+				target: `${package}.d.ts`,
+			},
+		];
 
-		try {
-			const content = fs.readFileSync(targetPath, 'utf8');
-			fs.writeFileSync(isomorphPath, content);
-		} catch (error) {
-			console.error(
-				`Error processing isomophic package : ${package} :: ${error.message}`
+		for (const file of filesToSwap) {
+			const sourcePath = path.join(
+				isomorphicFolderPath,
+				file.source
 			);
+
+			const targetPath = path.join(
+				isomorphicFolderPath,
+				file.target
+			);
+
+			try {
+				const sourceContent = fs.readFileSync(sourcePath, 'utf8');
+				fs.writeFileSync(targetPath, sourceContent);
+			} catch (error) {
+				console.error(
+					`Error processing isomophic package : ${package} :: ${error.message}`
+				);
+			}
 		}
 
 		// Delete other environment files for safety
 		environments.forEach((otherEnvironment) => {
-			if (otherEnvironment === environment) {
+			if (otherEnvironment === targetEnv) {
 				return;
 			}
 
-			const otherTargetPath = path.join(
-				__dirname,
-				'..',
-				'lib',
-				environment,
-				'isomorphic',
-				`${package}.${otherEnvironment}.js`
-			);
+			const otherTargetFiles = [
+				`${package}.${otherEnvironment}.js`,
+				`${package}.${otherEnvironment}.d.ts`,
+			];
+
+			for (const otherTargetFile of otherTargetFiles) {
+				const otherTargetPath = path.join(
+					__dirname,
+					'..',
+					'lib',
+					environment,
+					'isomorphic',
+					otherTargetFile
+				);
 
-			if (fs.existsSync(otherTargetPath)) {
-				fs.unlinkSync(otherTargetPath);
+				if (fs.existsSync(otherTargetPath)) {
+					fs.unlinkSync(otherTargetPath);
+				}
 			}
 		});
 	});
diff --git a/sdk/src/driftClient.ts b/sdk/src/driftClient.ts
index cf67b1406..046427096 100644
--- a/sdk/src/driftClient.ts
+++ b/sdk/src/driftClient.ts
@@ -4166,7 +4166,7 @@ export class DriftClient {
 	public async fillSpotOrder(
 		userAccountPublicKey: PublicKey,
 		user: UserAccount,
-		order?: Order,
+		order?: Pick<Order, 'marketIndex' | 'orderId'>,
 		fulfillmentConfig?:
 			| SerumV3FulfillmentConfigAccount
 			| PhoenixV1FulfillmentConfigAccount
@@ -4196,7 +4196,7 @@ export class DriftClient {
 	public async getFillSpotOrderIx(
 		userAccountPublicKey: PublicKey,
 		userAccount: UserAccount,
-		order?: Order,
+		order?: Pick<Order, 'marketIndex' | 'orderId'>,
 		fulfillmentConfig?:
 			| SerumV3FulfillmentConfigAccount
 			| PhoenixV1FulfillmentConfigAccount
diff --git a/sdk/src/factory/bigNum.ts b/sdk/src/factory/bigNum.ts
index dc08b3ec6..f74de0692 100644
--- a/sdk/src/factory/bigNum.ts
+++ b/sdk/src/factory/bigNum.ts
@@ -386,10 +386,42 @@ export class BigNum {
 		}
 
 		const isNeg = this.isNeg();
-
 		const printString = this.abs().print();
 		const thisString = this.abs().toString();
 
+		// Handle small numbers (those with leading zeros after decimal)
+		if (printString.includes(BigNum.delim)) {
+			const [leftSide, rightSide] = printString.split(BigNum.delim);
+			if (leftSide === '0' && rightSide) {
+				// Count leading zeros
+				let leadingZeros = 0;
+				for (let i = 0; i < rightSide.length; i++) {
+					if (rightSide[i] === '0') {
+						leadingZeros++;
+					} else {
+						break;
+					}
+				}
+				// Get significant digits starting after leading zeros
+				const significantPart = rightSide.slice(leadingZeros);
+				let significantDigits = significantPart.slice(0, fixedPrecision);
+
+				// Remove trailing zeros if not requested
+				if (!trailingZeroes) {
+					significantDigits = significantDigits.replace(/0+$/, '');
+				}
+
+				// Only return result if we have significant digits
+				if (significantDigits.length > 0) {
+					const result = `${isNeg ? '-' : ''}0${BigNum.delim}${rightSide.slice(
+						0,
+						leadingZeros
+					)}${significantDigits}`;
+					return result;
+				}
+			}
+		}
+
 		let precisionPrintString = printString.slice(0, fixedPrecision + 1);
 
 		if (
diff --git a/sdk/tests/bn/test.ts b/sdk/tests/bn/test.ts
index 444c44315..e4733dee6 100644
--- a/sdk/tests/bn/test.ts
+++ b/sdk/tests/bn/test.ts
@@ -11,6 +11,13 @@ import {
 // if you used the '@types/mocha' method to install mocha type definitions, uncomment the following line
 // import 'mocha';
 
+const bn = (value: number, precision: number) =>
+	new BigNum(Math.round(value * 10 ** precision), precision);
+const _bnPrice = (value: number) => bn(value, 6); // Price precision (6 decimals)
+const _bnNotional = (value: number) => bn(value, 6); // USDC precision (6 decimals)
+const _bnPercentage = (value: number) => bn(value, 4); // Percentage precision (4 decimals)
+const bnBaseAmount = (value: number) => bn(value, 8); // BTC-like precision (8 decimals)
+
 describe('BigNum Tests', () => {
 	it('basic string representations are correct', () => {
 		const bn = BigNum.from(TEN_THOUSAND);
@@ -108,6 +115,12 @@ describe('BigNum Tests', () => {
 		expect(val4.toNum().toFixed(3)).to.equal('0.025');
 		expect(val4.toPrecision(4)).to.equal('0.025');
 
+		expect(bnBaseAmount(0.001234).toPrecision(4)).to.equal('0.001234');
+
+		expect(bnBaseAmount(0.001004).toPrecision(4)).to.equal('0.001004');
+
+		expect(bnBaseAmount(0.001).toPrecision(4)).to.equal('0.001');
+
 		// Case 5
 		expect(BigNum.fromPrint('1').toMillified()).to.equal('1.00');
 		expect(BigNum.fromPrint('12').toMillified()).to.equal('12.0');