There's a 6 volt headlight relay on Ebay right now, but it's made for an early Volkswagen. Relays just eliminated long, small-diameter wire runs and reduced the voltage drop, resulting in brighter lights. On a 6 volt system, the difference in brightness was very noticeable, plus light switches and dimmer switches lasted a lot longer.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!