The modification is fairly easy and takes about an hour. I marked the size and position of the ground glass on the plastic screen. Drilled out holes in the corners. Sawed out the rectangle with a coping saw (or hacksaw blade). Sanded edges. Glued in supports with 5 min. epoxy. Glued in ground glass with 5 min. epoxy.
Happy with the results. Now easy to focus and compose.
Jon
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