After replacing the one bad rivet on Wednesday and letting the sealant cure, I re-pressurized the tank on Sunday afternoon. 24 hours later, the pressure reading was exactly the same, so the tank is good. As before, the zero point for the unpressurized tank was 16” WC, so I pumped it up by 12” WC to 4” indicated, which is really 12” x 2 = 24” WC or 0.87 PSI.
Before I install the tank, I needed to complete a few small tasks in preparation. First I shaped and then installed the breather vent for the outboard side of the tank. Next I rolled the edges of the skin with the edge tool (to ensure a tight fit) and then sprayed some primer on the inside skin surfaces that overlap the other wing skins. Lastly, I installed rivnuts for the maintenance access port, coating the rivnuts with JB Weld to make sure they stay put.