Riveted the stiffeners, prosealed, and clecoed the inner ribs. Once again, I found that not one of the marrying surfaces showed any evidencen of having been sanded or roughed up to accept any sealant. It's no wonde to me why these tanks leaked before. Well, it's done correctly now.
I am going to try and get both of these up to the point where all that is needed is the installation of the rear baffles. Tomorrow the ribs will get riveted and all areas sealed.