Page 17 of the V6 ACM install manual shows how to solder sleeve multiple pin connections with short 20awg wires into larger conductors. Same idea with the Alt Field.

If you want to go through the calculations you may be able to run a single 20awg for the alt field but it depends on the run length and alternator field amperage draw. (20awg gives you about 10ft at 5amps at cranking voltages)