I wonder if he has a way to make a setup for a 70 Charger. I tried to put headlight relays in 5 or 6 years ago but the headlight doors and lamps got all wacky. I later learned it was unique to the 70 model and the headlight relay the factory used.
You should be able to do them the same as any other Mopar of this era. The problem with headlights is that the power for headlights (originally) comes off the ammeter circuit, the MAD fix thing, so THAT can be low on voltage already
After that the power goes through the headlight switch, through the dimmer switch, and THROUGH THE BULKHEAD to the high or low beams so there's voltage drop X 3 more
So break the high and low beam wiring in the engine bay. Feed the bulkhead ends to relay coils, feed the headlight end to the relay contacts, and run a power feed to the other half of the relay contacts through a nice be wire and breaker
The relay/ motor wiring is fed separately through grommets in the firewall, it is not such a big problem
