I think I solved my regulator issue today, the dumb, easy way. To recap, I would set it at 9 psi, pull a few pints, and the next morning, it would be at 15.
I saw a tip elsewhere that there might be a bit of grit or other foreign material might be stuck in the diaphragm, and to blast it out. I disconnected the regulator from the gas lines, with the tank shut off, opened the regulator all the way, and blasted a few shots through. Hooked it all back up, and reconnected everything. 7 hours later, and it's holding steady.