Adding the last two stiffeners - N622RV Today in the shop, I finally finished the Prosealing of the stiffeners on the tank. I also tested the hand riveter and yoke to make sure it would work on hand squeezing the fuel cap rivets. I also double-checked all of the existing ProSeal seams to ensure I covered everything. I don’t know who said it, but I will repeat it. “If you know for a fact that your tank will not leak. Then it will not leak. It probably will if you are concerned that it will leak.”