I'm going to add some sort of anchor point, for attaching a safety rope, to my galvalume roof (some sort of shoulder eye bolt, but that is a different discussion). My question, what metal is best for this bolt ? Stainless is the obvious choice, but I gather it would have substantial galvanic corrosion. Should I just use zinc-coated or galvanized ? Or would it be better to use stainless, for best corrosion resistance of the eye bolt itself, and attempt to electrically isolate it from the galvalume panel that it penetrates, probably using the same silicon caulk I'd use to seal against water leaks ?