Original Xbox controller mod

Okay, so I have been here lurking for sometime and never really had much to contribute or ask till now. My experience is limited yet have always been intrigued in the mods and custom things others have done. I am starting to put together some tools for this first small task I want to do to one of my Xbox controllers and was hoping for some tips and or suggestions from the more experienced members here. My plan is to slim down one of my controllers and make it thinner. The 360 controller does not to my knowledge work on the original (different plugs I know, but meant even with modding) Xbox. So I am attempting to remove both save slot ports, have removed the rumble motors, plan to remove the potentiometer triggers and relocate them from the bottom to the front and and slim down the plastic casing.

The save card slots should be easy enough, but wanted to know if I could just remove the potentiometer triggers all together as I am using a madcats controller that has the extra black and white buttons on the front instead. I was thinking I could just solder them in place of the original triggers. This would be more of a button feel like the PS controllers. Wanted to know if this would still work or should I stick with the original triggers just remounting them. Also was looking for tips on the plastic. After I remove the excess plastic from the original mounting position and some from the hand grips should I use a fiberglass solution like in autobody work or is there a better way of remolding those places. I know some say to use bondo and some have 3D printers and make a whole new custom casing. I have no 3D printer or access to one but I do have plenty of hobby shops and general hardware stores that have plastic resins available. I welcome any tips and suggestions as I dont want to screw up my first mod....that bad anyway.

Thanks..microjunk