http://www.rcuniverse.com/forum/m_5239448/tm.htm

Just from my experience... counter balancing the rudder will add more authority than adding to the trailing edge. On the above thread I did both counter balance and trailing edge... but on my SSE before this one I did only the counter balance. When compared to a buddy who added about 1 or 1 1/2 inches to the trailing edge... mine way out performed his in knife edge flight. I'm not real sure on the technical explaination on this but from what I've read, the control surface (counter balance) portion that is in front of the hinge line tends to be more effective than adding the same amount of area to the trailing edge. As for the amount of counter balance... I chopped about 1/2 of the tail fin off and added it to the rudder (there's a pic in the thread).