It turned out that the parts we got from the plumbing place in Reno didn't fit, but they were not that expensive, so we didn't plan on rushing right back to Reno to return them. However, the office store from which we bought the fancy chair called us to tell us that the warranty replacement part had arrived, and if we brought the chair in, they could fix it while we waited. And as it happens, both they and the plumbing supply place are on the same street, albeit a couple of miles apart. So once again, as soon as we could after I finished work we headed into Reno again. First we went to the office store and gave them the chair, telling them we'd be back shortly (the plumbing supply store closes half an hour earlier than the office supply store). Then we popped down to return the part, which was not a problem, and returned to the office furniture store about 15 minutes after we left. They hadn't yet quite got the replacement part installed, but that was no problem. Eventually they got it into place, we tested the chair and confirmed that it worked as it should have, and thanked them for making good on the warranty.
We did not stay in town for dinner tonight, but we did have a couple more grocery shopping stops to make for things that are harder to get in Fernley. Lisa did all of the driving today, including driving us home, where we went over to Lowe's and got some more generic plumbing parts that she says should work for what she thinks she can do. If the plumbing problems get sufficiently difficult to fix, we'll buy a new toilet, although in this case we'd take care to buy he identical model to the one in our master bathroom, so that parts are interchangeable if necessary.
It's a good thing we had the chimney cleaned last weekend. It was cold enough last night that Lisa lit a fire, and I rekindled it when I went to work this morning. I do need to be able to feel my fingers when I'm typing.