AD,
There is another option you may want to consider. That hub is also the Corvette hub and it is made for GM by Timken. The full line of Timken is available at any bearing supply store except the stuff like that hub which is proprietary to GM. But in their same line of bearings they have three others that are the same bolt pattern on the hub side, the same dimensions, but with a 5x120 wheel bolt pattern. They are not proprietary and easily available, should be around $100 each. For about the same price as spacers, you can fix the problem instead of having to put a Band-Aid on it.