counter-balanced is the way to go (mass-balancing is not necessary - adding weight to the counterbalanced portion). You can even increase the size of the counterbalanced area to more than you see in those pics above.

That way you won't have to increase the overall area of either the rudder or the elevator.

Without these mods, the SSE has plenty of aileron action, adequate ele. and inadequate rudder at lower speeds.

I.F.