Made a bit of progress on the hardware front today. A trip to Jaycar proved fruitful and after a bit of marking out and drilling, the relay box is starting to take shape. It is slow going on the soldering with my 55 yo eyes but the end is in sight
I wanted to avoid the terminal block connections a lot of the commercial units employ because my existing power cables already have the screw-retained 2 pole connections. I also wanted to replicate the individual fused and LED indication for each output that I have on my existing power distribution box.
Here's how it is looking at end of play today.