[chap52]

I would assume that each connector on a new harness would me labeled?
When you receive the harness lay it out and using a wiring diagram label each wire accordingly and go from there. Don't wait until you are on your back to decide which wire goes where.
I am 78 and if you were closer (Tucson, AZ) I would give you a hand. That way there would always be one of us upright to call the Fire Department to help the other guy get back up.
I completely wired a 52 F1 to 12 volt using a Ron Francis kit years ago. Each wire had its purpose actually printed on the wire. Much too involved for your needs, but can be done.
Go NOS if possible and focus on one wire at a time. Keep us posted. Chap