I have done a few test with 14awg and 13awg wires on a 17.5 motors using 1s in my 1/12 scale. I used a stator IR tester and the 14awg wire does show 0.2 milliohms more resistance plus on a dyno loading up the motor at 6000 rpm at 4.2 volts the 14awg wires got warm and showed less power.
After that result, I never bother trying the 16awg.

Has anyone tried the new rs pro black edition 1s?