I went back to the stock metal gaskets too. No matter how careful I was the O ring gaskets would crush. I tried to make the cork gaskets work but just couldn't for some reason. You can find the copper spray at any auto parts store. Ask, don't look. Permatex is what I used. If the mating surfaces are perfect you won't need the insurance (copper spray) IMO. I used it because I managed to get some scratches in the surface with my one edged razor blade. Oops.

Les