Andy, I thank you for your comments and don't think anyone took them as being directed towards anybody. Since my experience is limited, I'm glad for the heads-up on the possibility of leaks. I wanted to let folks know I hadn't had any so far. But now I'll be watching for unwanted water in the water closet, so to speak.
Bob, a local RV shop installed mine. They tell me they went by the installations instructions, but I don't know what glazing material was used. The illustration in the manual showed application with what looks like a caulking gun. The gasket you have probably is the seal. You can find the manuals at Sealand Sanitation
. Sorry I'm not more help than that.