Your proclamation of the Melvins being one of the best bands ever is about 15-20 years late. It sounds as though it took the double drummers to push you over. Bumbershoot was a bit of a mess this year on every angle.
Yep, the Melvins set was buzzsaw-sharp. And the huge venue was indeed a weird juxtaposition to the last spot I saw them, at the Wild Buffalo in Bellingham. For what it's worth, Tool has often listed the Melvins among their two biggest influences.