I went with the GS 5515 on the rudder also along with using it's control horn instead of the GW servo control horn. I still had to cut my EPA back to 90 percent. I put the ball link on the rudder horn and tighten each cable and then ran another loop through the crimp tube before crimping. now my rudder is working perfect.
These GOTECK servo's are high voltage servos that can run on 7.2 volts