The contact-part of the switches I'm using in the 3D printed paddles are really small (only 0.7mm):
https://www.jaycar.com.au/0-7mm-spst...witch/p/SP0600
So these paddles need to be designed to "perfectly" fit the steering wheel's contour - so nothing gets in the way and the switch is pressed reliably.
I have not seen a BA/BF steering wheel in person (or an older Territory for that matter, though I'm sure the SZ has the same steering wheel as mine). I'm sure the older ones are different enough to the FG though for them to not work properly right now. I would need a BA/BF steering wheel to scan on my CNC machine and some extra time to align it properly on my 3D paddle model for it to work I think.
Then test that the washer/headlight stalks don't hit it! I'm also unsure if the plastic vs leather steering wheels have vastly different dimensions, but I assume they will be close enough.
My plan is for this to work on the existing device, but you will need to return (just) the circuit board (leave the wiring in place) to me for a firmware update. I've got a new firmware, but it needs thorough testing. I'll be installing it on my car tonight, and driving around for a while in the current mode (to make sure it doesn't try to enter the new mode in error). At the moment, the thing is only bench tested (but it is working reliably on the bench).
Then the only extra things that need to be done to "upgrade" is to pull the steering wheel off, solder two resistors (only one for the FG) to the button wires under the air-bag and bolt the 2 paddles on the plastic cowl at the back of the steering wheel. The device will automatically switch to the new mode next time it boots.
Sheesh, sorry for the long reply to a simple question!