I tested a particular plane setup. At 70-80amps 12ga wire was about 0.4v lower than 10ga, wire was 200mm, all else the same. 580 watts opposed to 480watts, 20% power increase. CLEAN Deans and CLEAN 4mm bullets have about the same current capacity. Bullets are far easier to use especially when the wires are at a minimum.
PCBs have no place in battery construction. They stopped using them in plane lipos a few years ago.