I decide to add a used GEM-602, yes it is not as nice as the new stuff but I only had the single stock units until now.
The question is how do you put one in a 3.5 inch hole? I was thinking no problem, bought the adapter plate and then after drilling the hole for the push button in the adapter reality hit. There is not enough room around the unit to put nuts on the back side of the 3.5 inch holes.
What have others done?