Agfa Isolette focus ring calibration

So I picked up an Isolette and of course it had a frozen focusing ring. That's all fixed (thanks to me stalking this forum), but when I pulled it out of the solvent and the goop had broken free, I was so excited that I forgot to mark where the two elements were in relation to eachother. So I believe that the focusing is approximately correct, but how can I make sure it's spot on without wasting film?

Stretch some Scotch magic tape across the film guides as a substitute for ground glass and examine with a 10x loupe. Or you can focus on the aerial image - rest a microscope slide (or other small bit of glass) with a mark or a bit of tape on the film rails. For extra accuracy you can space the slide back with a bit of tape between the rails and the slide to approximate the emulsion thickness and slight amount of film bowing in the gate.

I have an Agfa Soligon front cell that is absolutely frozen - a year (an actual year) in solvent, a hot oven, vice grips - nothing will budge it.

I'm going to try that, thanks. And sorry to hear about your Soligon. I soaked mine in Goo Gone for a few hours and it did the job. Luck of the draw I guess.

It worked perfectly. The tape was really dim, so it was a little difficult to work with, but I think I got it.