Hey Chance..... Im probably one of many who copied your design and built a Mortal Kombat themed cab in 2015 but cheaped out on the buttons and used single color LED buttons originally.
Well my job closed because of this stupid covid crap and so have a bunch of time on my hands at the moment and I am building a new PC for the cab and doing a facelift on it and just ordered Ultimarc rgb buttons and 2x ledpac64's......
Anyway, I originally had led lit balltops on my sanwa jlf's but decided to replace the balltops with white bat tops and stiffer springs and am thinking about just lighting the joystick shaft holes like you did. I ordered clear dust covers and rgb LED's with pigtails and connectors already installed, they will plug right into the pac64's and plan on just doing what you did with acrylic or polycarbonate tubing but have a question.....
Do you think a single RGB led would illuminate the clear tubing piece good enough if i scuffed the tubing up good to make it diffuse? I think you ended up using 2 per hole but I think you did some testing with a single rgb led at one point and wondered if you thought a single put out enough light to look decent?
I also thought about just angling a single rgb led up at the dust cover and just sanding the bottom of the dust covers to make them opaque/diffused, did you ever try that?
Thanks!