Hi Ray - the plate size was 4 x 5". Not sure how long it took the gel to set or if the plate was chilled, but I imagine that it was. Obviously, you want to develop the image as soon as possible after coating it so the emulsion doesn't continue to evolve. The chart was a glass plate (I think) that was placed in a very old looking projector - black wrinkle finish. But the projector looked to be very well made and the projected image was sharp. I don't know what they developed the plate in, but I doubt it was pyro.
Regards - Jim