I have mounted my gear using the self tapering screws that came with the gears. I predrilled guide holes and after that mounted the gear. I then droped some thin CA into the holes made by the screws. I can propably still change it adding a T-nut on the back and use nylong bolts. Will stringly consider it. What size nuts will you use? 3 mm (a bit less than 1/8 inch)? Not much room for the T-Nut but with a little of filing it might work.

This is my first retract installation so I am curious about the best mounting method too.

Regards
RCer.