Headlight relay

The other day i installed a relay on a civi truck to keep the low beams on when the highbeams are turned on. I was thinking of doing this for more light on my duece. I was going to use the high beam indicator light wire to charge the relay. Do you think the headlight bulbs can handle the heat, Amps?

Good question. Remember the "Milenium Reo" truck from Ebay? I think by reading the info the gentleman constructing it had a whole seperate system for just that purpose. I saved some pics.. Maybe this will help.