I'd go with 12 ga wire. I checked Belden's site and the 8251 runs 1.1 ohm/1000'. For 2 wires (back and forth) it will be 2.2 ohm/1000'. I think 12 gauge wire runs 1.6 ohms (or so depending on temp) for a round trip. So I think the 12 ga will actually give a slightly lower resistivity. It's going to be a lot easier to work with too.