The spring should have quite a bit of tension equally on both sides. The question is where exactly is the springs mounted on the tailwheel? Mount seperate control horns as low as possible on the rudder. I've never favored the spring method. I usually direct connect with a control rod from the rudder servo rod. If you have pull-pull then run a small tube(like an antenna tube) and do pull-pull on the tailwheel also with both lines coming out of the same tube from the bottom of the fus.