Headlight relays have been in use since the 1940's so it's nothing new, and there's a very good reason to do so. Using them on 6V systems is particularly beneficial. Every time electric current passes through a switch or a connection, a tiny bit of voltage is consumed to push the electrons through the connection. It's called "voltage drop". That leaves slightly less voltage available to do the job once it gets to the headlights. Stack up 5 or 6 such connections from the battery, to the ammeter, to the light switch, to the dimmer switch, to a junction block, to the headlight filament, and then negotiate a similar ground path back to the battery. Auto makers are notorious for pinching pennies and using the smallest gauge wires they can get away with. It affects their bottom line when they're producing millions of vehicles a year, and their shareholders don't really care if you can actually see where you're going. You'll need to carry a flashlight to check if the headlight is actually burning.
Now- - - -run a HEAVY wire , like a #8 or so, from the battery cable at the starter to the radiator core support, and tie it into two relays, one for high beam and another for low, and run a heavy ground wire back to the engine, body, or frame (wherever the battery ground cable is attached). Use good, new wires (maybe #12 or so) from the relays to the headlight connectors, and back to the common ground. Use the signal from the dimmer switch just to trigger the high and low beam relays. You've just eliminated 80% or so of the connections the headlight current must negotiate and made the headlights noticeably brighter in the process. Is it worth it? Thousands of purchasers of aftermarket headlight relays have certainly thought so, for as long as I can remember!
Jerry
