It's been a while (been doing other stuff) but I finalzed my driver board and libraries. Clock has been working nicely for appx. 2 months now, as a pcb that just plugs into the Eurocard socket on the back of the board.
A few notes:
1) Current: who cares? I accidentally picked a driver that limits to 3A pulses, and the timing is really fast. Just needed the right mix of caps and types to make it consistent.
2) I canned using GPS as a time source. still using Wifi and NTP for ease.
3) I added an enclosure, just ordered the cnc routing. something mid-century modern so my wife won't marie kondo it in 5 seconds - here's an exploded asm and a final asm pic:
PCB (didn't model the dots)
pcb with frame/enclosure for power supply
Shameless ripoff of this general bezel design from here:
All in all, not too bad. if you want me to post pcb files etc lmk.