1968 4 speed reverse light wiring routing

Wiring diagrams not so bad for me, just takes patience to follow them through with the correct color coding on wires.
But when it comes to physically knowing where the factory mounts the actual switch, relay, sensor, routing of wires, etc.; that's where all the time gets spent browsing through online pics. Especially when what you are looking for isn't on the car because previous owner(s) did incomplete job of restoration.