Be prepared for some pretty slow choke release trying to run 6 volts to those chokes. They're designed for 12 volts, so you'll have about twice as long a release time as is intended. I like to use a mid-1970's Vega fuel pump switch in the oil pressure gauge circuit to turn the choke heater on and off. If the engine stalls during warm-up, the heater doesn't continue to release the choke. A 16 gauge wire is plenty to carry the heater current. I'd reccomend using a wire from the back of the ammeter or the voltage supply wire to the ignition switch, with a 10 or 15 amp inline fuse to provide power to the oil pressure switch.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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