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.