I switched to using just a piece of new 1/4 inch glass, but I really liked using the contact printing frame, especially since I am not using a real darkroom and the frame helped hold it all together. And I liked being able to dodge during the printing process, which I can't do with the diffuser in place, as you identified.
Originally Posted by JBrunner
I can't figure out how to get the old glass out of the frame. For now I have taped off a section of the frame that is scratch-free, but it forces me to use the lower left hand corner of the 8x10 sheet rather than the center, and I would not be able to use a larger (5x7) negatives.