Loving this thread @Luke, thankyou for sharing!
I have designed several CNC’s in CAD but not actually built one yet - all are quite similar to your design.
If you have any more issues with electronics, I have upgraded my SO3 XXL to a Gecko G540 and LinuxCNC, and I cannot recommend it enough - it is absolutely bulletproof, no issues with VFD/Spindle control or electrical interference at all.
Thanks again for the inspiration, might be just what I need to start my own build using the SO3 to make parts