To revive this old thread... I got a piece of glass 0.5mm thick and installed everything as it was originally. The glass was very difficult to cut without shattering it, and in fact I never got a usable piece and am ordering more this week, but I got some in there to see how things work. Because of the gap between the film and wedge, there is significant bleed from one step to the other, making a clean reading with my densitometer impossible. When the new glass arrives, I am going to install the tablet under the glass, closer to the film and see how it works there. I also found the potentiometer that controls the time for the light. As I wrote earlier about this machine: there is a sensor that measures the light inside to compensate for loss thereby extending the exposure time. This potentiometer allows me to adjust the exposure time to just shy of 1/2 a second. This should eliminate problems with reciprocity. I can easily remove some of the ND layers to get a good exposure.