The rivets with the round head are called "shave head" rivets and they require a special (meaning expensive) shaving device. I have one if anyone at the Dec get together in Florida needs a rivet replaced. I have a bag of the special, gasketed rivets too, but don't recall the length. They seal well and look good as rivets go. Essentially they give the look of a :buck head rivet" while allowing a single sided application.

I got my PhD in Rivetology while converting my old MCI. My hands still hurt thinking about all those rivets. Should have bought the air actuated gun I guess.

Corey