In response to MTK, no I am not wrong on that you can use smaller servos. Years back (in the late 50's and 60's) you did not have the higher powered servos as you do today and we flew 1/4 scale by making sure we could handle the large surfaces. Both static and aerodynamic design allowed this with no problems. We also occasionally used boost tabs to do the same thing. I still use boost tabs where lots of aerodynamic force is required, especially on the rudder.
And, in response to karolh, hunting is NOT the same as flutter. It is where just a slight movement away from neutral will let the surface ahead of the hinge line try to overpower the servo and, if on the elevator, causes the plane to gallop through the air, not with the surface in sustained self oscillation of flutter and occurs only when the surfaces are in the neutral position. The same problem with hunting can happen with boost tabs if the boost tab area gets much more than 20% of the moveable surface.