Productive day! This is the first of my (now possibly four!) 5m strips of leds, cut into 15-led sections and wired with connectors. Miraculously they all worked first time! Left to do on these is put heatshrink stuffed with E6000 over the ends and double the wires back, secured with more heatshrink, for strain relief.
The reason this is a breakthrough is I now have a working, “square” display I can start coding for.
