How much will 70cc heads raise my compression? Also how much lift?

I remember a while back seeing multi layer steel head gaskets that were like .025 compressed and were around the price of regular head gaskets I don't remember if it was mopar that mad them or who? Since then I'm having trouble finding them, I've never messed with cometic head gaskets but aren't they a multi layer steel?

Would it be safe running steel shim head gaskets on aluminum heads? They wouldn't warp my heads or anything? Say if it gets a little hot? The block looks like it had been resurfaced at one time, engine looks fairly fresh I think someone must have did a rebuild with stock Pistons or replacement Pistons.

I'm running stage 6 heads that I got a pretty good deal on, they had been done by David porter, and at first I was going to run some iron heads with the steel shim gaskets and shave them, then I managed to get a little more $$ for my budget and was going to get a set of stealths or sidewinder heads but I ran across these for what a set of stealths would cost and I figured in the long run being they already have better flow numbers than the stealths, and luckily I'm running a low deck block so header fittment won't be as much of an issue with a high deck block with raised ports. they would be a lot better head for when I stroke it, which I'll probably either send them back to porter and have more extensive port work done and maybe even bigger valves installed.