Stacking head gaskets? I’ve never done that. What I did do a long was back was use the MP head shim to drop the compression down. It is a .060 thick steel shim you use with a gasket on top. You could use one on both side of you wanted to. I did not. What it did for me was drop the ratio from over a 10-1 engine requiring 93 to an engine that used 87 quite well.
I doubt you’ll find the MP head shim anymore. Now, I just call Cometic and spec what I want and they make it up. What Cometic does is use thin steel to make there gaskets and stack them up for the desired thickness. I have used them several times without issue. As thick as .100 thick, no problem.
Cometic rivets them together. The rivets are outside of the contact area of the block and heads. Nothing special needed for there use.