For the neutral safety switch drawing, you need to look at UPC 6, sheet B10. The schematic (UPC 12, sheet D2) shows BOTH the standard transmission "clutch pedal operated" neutral safety switch and the optional "Automatic Transmission" switch. You won't have both (unless the car's been converted from an automatic to a manual transmission!)
For automatic transmissions, the neutral safety and backup lights are incorporated into the same switch. For manual transmission cars, there are two separate switches. The neutral safety switch, located on the pedal support, and the backup light switch, located on the steering column.
The neutral safety switch for the manual transmission uses 12 gauge purple wires on both sides of the switch. (For automatics, one is purple and the other is purple with a white stripe)
The 20 gauge pink wire comes FROM the direction signal flasher TO the backup light switch. The 12 gauge light green comes FROM the other side of the backup light switch TO the rear harness, and then on to the reverse lights.
I'll let someone with a 69 post pictures, but that should get you started.
Ed