I have a set of those Servosticks too and I have never been able to make up my mind about which machine to put them in. Don't mind using a toggle switch if I need to with those myself really but the U360s natively as analog sticks would be like magic at this point.
I hear you! I ordered these back in 2019, and only just installed them.
I sold my second-last arcade machine, and got the bug immediately once it left - so I've been completing my last machine ever with these. I will say they are a huge step up from the joys I had in my other cab - I sprung (heh) for super-tight springs and longer shafts, and they are a dream.
I don't want to have to select using a button, although that is a possible solution. I've read too many notes where people have the joys automagically switch from 4-8 way based on the game, and selfishly, I want that.
As I noted, if and when I have 'the' solution for me, I'll post up here with any help I can provide.
EDIT: OMG SUCCESS!!! While I am only partially done, I found a Wayback Machine link to RGBCommander Beta 0.4, downloaded and installed it onto my Pi, and tried their Dev Tool "rgbcmdcon" to run commands. Running "set,stick,4", I heard the motors engage, and the joysticks both automatically switched! Running "set,stick,8" switched them back.
Now, I have a lot more learning to do to try and determine how to make each game automatically trigger the switch between 4 and 8 way, but I am super happy with the current progress! (I will definitely be writing up some instructions on the site for anyone interested as well.)
SECOND EDIT: After reading some config files that came with the app, it said that it "listens" for the configuration and sets the joys accordingly. As that is, I tried it after installation and OMG it's already configured and works without any additional config from me!
I selected and started Pac Man, and the motors engaged and set the joys to 4-way. I exited, and the motors engaged and reset the joys back to 8-way. I tried Double Dragon, and they remained at 8-way. I tried Galaga, and they switched to 4-way.
You cannot believe how happy I am with this. Hope this works out for others as well!