Thanks for all the replies and the good points. As for the Felpro 1008's, I don't have any idea either why they are so large. As for the edge gap, I have taken apart my racing 4 bangers and not ever found carbon build up. But, it might become a problem for any engine with excess fuel or oiling or or carbon fouling.
I think we are going to put on a 1008 and measure how concentric the bores are and use that as our guide to see if we can use the 4.080" or the 4.125" Cometic. The .032" gap of the 4.125" does not seem all that large.
Edit to update: We put the Felpro 1008's on and found that not all the bores were perfectly centered on the gasket holes. Cylinders 2-4-6-8 were pretty good, but 1-3-5-7 were all off a bit vertically. So 4.125" is will be.