Hmm. The "no FIPG" ship has long sailed. haha. I used it on the cork gasket, and in place of a gasket for the water pump. Is the issue just that it's a pain to get off next time?
I still have a leak after getting it all buttoned up. I can't really tell where it's coming from but now I'm thinking it might be the cover plate.
I've decided to live with it for now, it's at least a bit better than it was!