My experience with new wiring is limited to just two restorations, my COE and my '37. Both are stock restorations. Before I placed the battery in the COE I used my $10 ohmmeter and tested the the battery leads. Oh oh, I thought I had a short, but it was only a light switch in the on position. With everything off, I had no continuity and safely placed the battery. My next project was my '37 and when I did the same thing I had continuity, with all switches off. Long story short I found the tongue of the windshield regulator touching a post on the headlilght switch.
The point of my story is to avoid frying your expensive harness or starting a fire when doing major work on a wiring system, use your cheapo meter on the battery leads to be sure hooking up that battery won't cause you serious grief.
Kent