I managed to find enough normal-sized air couplers laying around the garage to get the squeezer hooked up, so I was able to get the rear vertical stabilizer spar riveted together:
(Note that I keep an ample supply of lubricant available to make the work process go smoother)
The next step has you rivet the VS ribs to the front spar. I managed to get the upper and center ribs attached, but the geometry of the lower rib/spar interface has me stumped. I guess I'll either figure out a way to get the squeezer on those rivets, or I'll just smash them with the rivet gun. In that case, I have to wait for the new air fittings to arrive on Friday so I can get my regular air lines hooked up again and run the rivet gun.