Hello Marcus,
I think your order of plans is well chosen. Starting easy, cheap and in the house is how I confirmed for myself too that I could make it work. Then building it onto the tractor is the fun part (maybe also most challenging but OK). I am happy with the steering motors now and maybe someday I will get into hydraulics.
- I use MMA 8452 (blue rectangle) which works fine. I think either version is good, but would like to see this verified too.
- I found it doable to start with an arduino with terminal block adapter for just testing the basics in the house. You could bolt everything in a box and hand-wire like most did a year ago but really, PCB is the way to go.
- Also very eager to test the double antenna system which simpleRTK2B is perfect for. They have an elegant solution with 2B + 2Blite on top. I have a BNO but haven’t used it the last year so maybe it’s worth to wait.
- no experience with radio
- User @torriem had a topic in the combine forum on this. It was possible to use as base station for Trimble but needed some specific settings on the messages going to the Trimble I think.
- If it has 3 pins, try to identify 5V and GND. Maybe you can find the info you need here: Steering angle sensors