DualBL ---- in a TC3 with a 6-cell C40 7S, I had the spinning problem when my pack was up front (foam spacer at rear). The car spun as soon as I hit the throttle. When I moved it back, the spinning just disappeared. Must have needed the weight at the rear. I have gold springs up front and silver at the rear. Front toe-in is about 2 deg, neg camber is 0-1 deg. Rear toe-in is 3 deg, 0-1 deg neg camber.
I don't know how this applies to a car with 16 cells.