Sometimes you are just fighting a vertical CG problem (i.e. like the piped ships having the pipe below the fuse creating an inward roll moment that adds to the inward torque of a counter clockwise, tractor, motor rotation), best is to get that VCG in line with the leadout tip exit then use the flaps as minor trim. Cool system, I have used twin flap horns with ball links through a top hatch. The side slot looks cleaner, will give it a try.
Best, DennisT