I also have a 9650 401 combo..use the horn with the least amount of distance...In other words get the ball link closest to the servo shaft as possible..I used the round horn and put the ball in the closest hole to the servo shaft...As far as the Tail drifting, you shouldnt have any...Check out all of Finless bobs vids...Are you sure your gyro is in HH mode...Make sure your light on your gyro is always always on and not flashing...