Tonight's session started by installing the fuel drain flanges on the underside of each fuel tank skin. These flanges will eventually get the sump drain valves screwed into them when done. I started by applying a layer of tank sealant to the contact surface of the flange and then hand-squeezing the rivets that hold it to the tank skin. Then I cleaned all of the excess sealant and applied small blobs on top of the shop heads since those will be on the inside of the tank.
Next I started the preparation of the attach brackets by hand squeezing on the various nut plates, shims, and bearings. This part went almost perfectly except when I riveted the shim to the bracket first and tried to rivet on the nutplates on its overhanging section. There wasn't enough room to use the squeezer or pneumatic riveter in this assembly order, so I had to drill out the shim and attach the nutplates first. In any case, both attach brackets came out fine and it's onto the next step.
What's next? Attaching the fuel cap flanges, and then maybe a final test fitting of all the ribs before I actually start riveting them in permanently.