Honestly, the best way, money aside, is to drop that motor in a shipping crate and send it to a reputable engine builder to have it done. No offense to you at all, but what if you miss something else? You're already going to be into the motor for more than it would have cost for a builder to do it the first time. Let's face it, the money is an issue, or you wouldn't have asked for opinions on how to fix it without having to swap pistons. The thicker head gaskets will allow the compression to be lowered enough that there is no need for a $600 cam swap. You can use your existing cam.
Regardless of Mr 67's opinion, the gasket does the same thing as changing the pistons, and he still hasn't explained how gasket volume is different than piston volume. If you are still leery of the gaskets, call Cometic directly and ask their opinion. They have a reputation as the best Racing gasket manufacturer in North America, if not the world. They will give you a straight answer. I guarantee it's been done many times, for many reasons. It's your money, how far will it go?