When you consider the need to derate due to the high heat conditions, I would suggest 18 AWG as a minimum. Should be over kill from a pure ampacity standpoint.
Dude I would HIGHLY recommend 12 guage wire,solder,crimp and heatshrink ALL CONNECTIONS,and use dielectric grease, AND KEEP your wiring as short as possible to prevent current loss,do that and you will be fine!!!!!!!!!