Works! There are some finer details to finish in the switch handling, but all the front panel switches behave as they should except under some 'corner conditions' that need to be ironed out.

After finishing up today, I brought the two prototype PiDP-8s to our local hackspace/vintage computer meet and we booted up OS8. Jos, our very PDP man - if I may say so - kindly brought along some paper tapes with the BIN loader and FOCAL. As well as a small handheld paper tape reader I think I can clone into the PiDP.

Priority now shifts to getting the acrylic cover plate. The temporary paper one is getting on my nerves.