Hi, Tahoe Ed:
Great job with F550...im worked with them and fly normally 2,8 km far away and 2,8 km back, total 5,6 km with camera and 3 kilograms, 6,6 amp 4S and stock motors with 10" DJI props.
Only 1 motors burn out in fly because the system was to the edge (4S and stock motor with 10"...