This extension is designed to keep the twist axis, and be completely removable. No cutting or modifying the original parts.
Edit: To adjust the drag and so the twist axis centers properly a small amount of grease can be used on the shaft, and the tension on the 5 lower screws can be adjusted.
Print settings are PLA, .4mm nozzle, .2 quality layer height, 4 Parameters, automatic support enforcers and support on enforcers only. I also painted on supports where the print will contact the shaft. Support on build plate only should also work. NO Brim.
You will need
Philips head screw driver, 3mm Hex wrench.
M3 screws and nuts 7 of each. The screw lengths needed are 1- 6mm, 1- 8mm, and 5- 12mm or longer.
Hot glue is optional but very useful for keeping the wires in place.
Needle nose plyers are also optional but great for removing and replacing the trigger pin. Also great for placing the rubber caps under the buttons if they fall off.
Steps
Let me know if there are any problems with your results.
UPDATE: I made the holes for the nuts slightly larger. I added models 5.55mm wide hex nut holes. The originals had 5.45 wide hex nut holes. (This is the outer Hexagon size, they are still all sized for standard 3mm screws.)
The author marked this model as their own original creation.