Decided to bite the bullet and seal up the back baffle on the left tank. Watched than Vans video one more time over the weekend and felt prepared. Laid out all my tools and got after it. Cut a little off the tip of the proseal applicator to produce a little thicker bead. Laid the tank on its side (bottom down) and laid a nice bead just below the rivet line. Flipped it over and did the top. Then did the end ribs and got big blobs into the corners. Put just a small amount in the outermost holes of the interior ribs per the video. Dropped the back baffle in place without smearing it around and cleco'd every hole in the skins and ribs. Looks good so far. Set the outermost blind rivets in the ribs. Then removed every other skin cleco and set the skin rivets with the squeezer. Then removed all but every 10th cleco and set the remaining rivets. Repeat on other side. Then set the blind rivets for the zee brackets. Put just a dab of proseal on each hole and swirled each rivet then set them. I don't know if the zee brackets on the RV-10 are wider than older models, but I had plenty of room to get my rivet puller on the rivets and did not need to use the wedge method. Got it set on its back to let what little bit of sag in the proseal work for me. Will let it sit there for a few days and cross my fingers. All and all pretty easy, but who knows. 9/7: finished off the tank this morning countersinking the few remaining holes in the skin and setting the last few rivets. The proseal left on the plate appears to be fully cured so I bit the bullet and strapped on a balloon to the vent line and pumped it up. It appears to be holding and no sign of bubbles in the soapy water. We'll see. 9/10: balloon is not holding. Suspect it is leaking around the balloon itself. Need a better clamp. 9/12: wrapped the vent tube with silicone tape and pulled three tight zip ties. Seems to be holding.