1960s !961 cowl to hood side seals

[MidModCad]

I'm installing new left and right cowl side seals (bought from Rubber the Right Way), and running into fitting issues. The cowl mounting area slants and twists and isn't quite even which makes it impossible to mount the rubber flat. I wind up with little gaps here and there.  Also the 3M super weatherstrip sticks fine to the painted metal, but not much to the rubber.  I'm following the directions exactly: two thin coats on each surface, tack dry, then one bead on one surface, press firmly.  Also roughed up the rubber with sandpaper.  Still peels off way too easy.  Anyone done this before? 

[The Tassie Devil(le)]

I would be using Brakleen to completely remove any release agent that could be on the rubber parts.

Bruce.

[MidModCad]

I did scrub with soap and sand pretty thoroughly, but maybe your suggestion is needed as well.