Another option you might think about for sealing that edge Jaydee is good ole Permatex Blue form-a-gasket. I've used it without any other gasketting material on my car coolant systems (heat and pressure there) and never had a leak

Once it sets up it's a rubbery like substance, and the teflon in it flows very well into the surface imperfections. Not what you might want for a production wb, but for testing and one-ofs it should work just fine.