Okay, so I went to Lowe's and bought a whole bag of clamps... Which included the ones we discussed above, plus a few other sizes.
https://www.lowes.com/pd/IRWIN-QUICK-GRIP-1-in-Clamp/1000235643
I think I tried just about every possible combination of clamp, method of attaching it, and method of using it... But found them to be completely worthless for installing a dryglove onto an Ultima Dryglove Ring. I have no idea how y'all are using them, but no matter how I tried, they'd pop off the moment I pulled on the rest of the o-ring and glove combination to get it over the Ultima Dryglove Ring.
If y'all are really using clamps to install gloves onto dryglove rings, please post a video of how it's done.
One thing I DID finally get to work today was this: I have a bathroom sink that has a slightly raised lip on the edge of the vanity... A "normal" installation of a "normal" porcelain bathroom sink, rather than a "sunken" installation. I was able to sit the Ultima Dryglove Ring on the vanity countertop, up against the edge of the sink, and basically use that to hold the ring still while I worked the o-ring and glove combination onto the Ultima ring.
Basically, this provided the same kind of idea as the "small wood disk bolted to a workbench" idea, but without having to custom-make the installation disk thing. It clearly didn't work as well as a disk would, but it was close... And demonstrated that the disk is totally the way to go.
...So I'm gonna build a new workbench for myself in the shop... And install a dryglove installation disk.
Meanwhile, though, I got four sets of the Ultima Rings loaded with SHOWA 720s today.
Clamps? No way. I'm throwing the BS flag until one of y'all makes a video showing it can be done.