Paul,
I have a recording console from the late 80s that uses eurocard backpane connectors. Its was based on a z80 and follows that standard. I have attached the connector detail schematic for the backpane, it might...
So my project is nearing rev2 - hopefuly the last prototype. Thankfuly all issues have been ironed out with REV1.0 pcb...
I have a load of WS2812 inside the main unit, and I break out to another WS2812 strip outside...