Interesting, Tulex. Again, without knowing how thin the head gasket is, and how much was removed from the head, it's a hard call. Sounds like you have a solution, but I have never heard of such a thing.
I should say, overhead cam cars need a shim between the head and block at times, so the timing belt will line up correctly.
Thankfully this isn't OHC. When I think about it, the numbers don't add up, but it works. I mean, even if the gasket is .010 thinner, and I took off up to .020 from the head, I shouldn't have to shim it any more than .030 where I took the most stock off. But, the thickest shims I had to add were .048. That gave me .002 clearance between the rocker and valve stem. So, anything less than that would have held the valves open. So, either the valves were being held open to begin with to some degree, I took off more than I thought, the gasket is thinner than I thought, or some combo of all three.
After we got it together and he took it for a ride, he said it has way more power than it ever did.