Hi Guys, I need advice on running duel batteries on my Fc40. My setup is : Tarot T2 Gimbal with Gopro H3, 9" P2 props. With standard 2200mah battery I get 7 min flight time on total take off weight of 1.3kg. Now I want to add a Boscam fpv on and planning to fit two batteries in order to increase flight time. What would be the best mah to run duel to get max flight time with added weight. I was thinking 2x 1800mah. Also can I power the fpv of one of the balance cords or should I add an extra 800mah for the fpv.