My husband used vulkem and alcoa sealing the rivets. I am posting a link to his thread about what he did... you might need to scroll down a bit.
Are you asking about the rivets you put on your outside skin? Did you use olympic rivets rather than bucked rivets? We bucked all the rivets on the outside skin of our trailer. Used olympic on the inside skins where we couldn't get to the back of the rivet.
I would seal everything as well as you can with something that will be a bit flexible as well as a really good seal. It will be interesting to see what others have done!
Mrs. NorCal Bambi (traveling in S Tardis)