Correct way to measure piston depth?

Yeah, those puppies are hiding down in the hole aren't they. What do you guys think an acceptable compression ratio is for 93 pump gas with iron heads?

Bobby, am I correct that with just a square decked block with the KB167s and the 302 heads without being milled at all should give close to 11 to 1? Wow, I really didn't expect that. I thought that basically zero deck with the KBs and no milling of the heads I would be in the 9.5 to 10 area.