i am going to be showing this from my already modded paddle so you will have to do some steps how i say and not what it shows.
So first open both paddles and joysticks and completely dismantle them including removing the wires. then get a piece of thinish plastic that can be cut to fit loosely in place of the joystick hole
Then before gluing it in, drill a hole as close to center as you can. start as small as possible til you end up using a 3/8 inch drill bit. Then cut the rubber joystick cover around where the old joystick use to be.
After that put the potentiometer on the plastic still not gluing down.. Needs to be put on in this direction
Next put the boot on and put the plastic piece with potentiometer on it in place(note: the joystick is not square so you will need to find right direction to make the pot center). With the boot on and the pot centered shove the knob all the way on. It should center itself with the knob over the boot. so with the knob centered we can glue around the edge of the plastic piece as shown in pic above. next cut a hole (preferably with a dremel, but mine was broken so i used needlenose pliers)on the board to make pot fit. Make sure the pot does not touch any edges so it is not making contact. Also you need to solder a wire to fix where we broke the trace.
Next cut the platic down on the center pin on the bottom plastic piece.
Now pull off the knob and shove little pieces of paper in it until you have enough to make the knob sit over the top of the 2nd rubber bump on the boot, but not rub against it.
Now run your paddle wires through the hole and solder to the board removing the old metal pin connectors. Note that you need to adjust pot wires and the jumper wire to avoid being crushed between the board and posts. reassemble the bottom and screw together. This took me about 30 minutes to do both paddles. Also as you can see I just learned a lesson in super glue fumes. let fully dry before reassembly