I'd like to thank all the folks on here that patiently answered all my questions, plus the countless resources on the internet that many people have selflessly provided. A year ago, the only thing I knew about electronics was how to use a soldering iron. Now I know enough to be dangerous (and to actually build my first nixie clock). I settled for a one-tube clock, because I found that I used my testbed for that, so I could light up the various tubes I have been buying. I can also use it to condition cathodes and display digits one at a time so I can test them or take photographs. In the spirit of giving back, I documented the project at
https://hackaday.io/project/28220-one-tube-nixie-clock.