I have some joystick extenders, I think they will fit where the screw for the shaft is, or maybe i can have something fabricated.
If it's an M6 screw, then that might work well and it will add some space so the 2nd wheel clears the spinner opto.
If it's not, get a long screw and spacer to mount the 2nd encoder wheel.
The stick is about 1.5/2 inches from the case wall. Could I just screw an optical sensor or magnetic reed switch to the side of the wall?
Sounds like a good idea.
Not sure which reed switch to recommend, though.
Hopefully you can find one that has a fast enough response speed and has some screw tabs.
If you can't find one with screw tabs, you can hang the reed switch by the wires using 2 very small loop clamps/adel clamps.
For the optical sensor, I found this on Amazon, would something like this work? This will be pretty awesome if it does work, and seems not to complicated.
If you do go with an optical sensor, the one you posted might be difficult to work with because of the lack of mounting tabs and how shallow the slot between the LED and sensor is -- very little wiggle room.
It might be fine for encoder wheels with an outer rim, but a one tooth encoder wheel can get out of alignment and jam up if the red part of the wheel I posted earlier isn't riding in the slot.
One good bit of news is that 2018 and newer X-Arcade encoders don't use an isolated ground for each connector like the old ones did so that removes one possible issue mentioned in a previous post.
https://support.xgaming.com/support/solutions/articles/12000003233-advanced-byo-kit-installation-diagram-with-wiring-schematic-NOTE: The ground wires are all ground, so you can use any ground with any input as needed.
Scott