Wiring R90/6

[chasbmw]

I bought a new diode board/starter relay wiring loom for my 74/75 R90/6

Did not take proper notes so have a couple of queries

Starter relay wiring
I have from the new sub harness, a red a black and a blue, the existing wiring from the main harness gives me a second red and a black, a double green/ blue and a blue/yellow.

I think I have the locations on the relay, but the co ours don't seem to relate to any the wiring diagrams that I have seen!

I also have a thickish black on the engine side of the wiring harnes, which I assume goes to the starter solenoid, with a smaller black that will connect to the points ignition.

When using a multimeter Can I use it to check which wire is which? For instance I would like to make sure that I have the correct black wire for connecting to the points ignition?

Good luck with the hernia rob, hope that you make a swift recovery

Charles