1979 K20 with 350 engine. Newly rebuilt. Had a little valve issue initially, but we are on the mend now. I measured the piston depth in the cylinder and I am at .026. I bought the Fel Pro 1094 steel shim head gaskets that are .015 thick, which puts me at .041. The instructions that came with the gaskets talk about needing a very smooth surface in order for the gaskets to not fail. It goes on to say that if they are not smooth, coat both sides of the gaskets with a sealer. My block is basically fresh from the machine shop and heads are super clean, so I think I'm good. But, I have a can of copper spray gasket sealer, so any harm in spraying them just for extra insurance? Will the copper spray increase the thickness of the gaskets to any concern?