After thinking for several weeks about the rivets that I had installed to plug the machining holes in the end ribs for the fuel tanks, I decided that I just wasn't satisfied with them. I decided to drill them all out and order replacements. The biggest problem was the rivets were simply too long to properly set. Installing using a couple of different methods into a piece of scrap ultimately led to the right procedure. New rivets are on order. Finally was able to use the new rivet removal tool from Cleaveland Aircraft Tool...awesome.