At last the finished product! Fully soldered with paste and hot air, with terminals mounted and mounted in it's DIN rail enclosure ready to go.

Level shifter powers up. No smoke. Unfortunately it doesn't work correctly because there is more current coming into the base of each transistor than I anticipated. It's enough to hold all transistors on. So I'll try getting some mosfets with the same pinout and seeing how they do.

I had a go at some SMD soldering with solder paste for the level converter board. It came out OK.

The PCB for the 12V to 24V has arrived.

What's a Loxone and why does the stupid thing have such a low input impedance? The reason is this chip. HVS882. It's an industrial input serializer chip. The input impedance is only 10k. This chip operates in a "window" mode for detecting "on" vs "off". With the recommended 4.7k pullup on a 24V supply, this leaves things very close to the 16V threshold that the chip requires for an "on" state. So I've started using 3.9k pullups which gives a little more room for movement on longer cable runs where a few volts can potentially be lost bringing it under the required 16V.

LED Lighting control box mounted and installed.