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

assembled pic

 Shameless ripoff of this general bezel design from here:

https://hackaday.io/project/26220-7-segment-flip-display-clock

All in all, not too bad.  if you want me to post pcb files etc lmk.