Hello Glenn!
Where applicable I drill two holes with a 0,6mm drill bit, and you can get a lot of nice 0,5 - 0,6mm wire from those thick cables that wire the car battery - just get a hold of a scrapped car wire harness. I've seen a lot of those since I started working for a company whose main business was making automotive wiring...
Hope it helps and have a nice day
Paweł