So ... I ... uh ... called 3M. I read reviews and questions sections in ads and 3M had replied asking that people call them, so I did.
A human picked up the phone in about a minute and answered all of my questions and referred me to another similar product that they recommend for exterior use because it has some sort of UV protection that the other does not. It is a whooping $.12 more! The bastards and their bate and switch.
Prep looks simple enough. Clean with soap and water, buff with fine grit sand paper, wipe with "solvent" (I'll be using denatured alcohol), set a bead and screw the cover in place.
Is there a way to seal or store the tube for future use?