I worked on an RV-6 a few weeks ago that had coil springs connected to the rudder pedals to the lower longerons, ostensibly to take out the slack in the rudder cables. They added so much stiction to the system that at low speeds, the plane would fly along happily with the slip/skid ball a full ball out. Pick a side and it would stay there. Landings were miserable since the plane wanted to slip or skid, it was difficult to get it centered. The owner (not a builder) assumed that's how RV's are. I pulled the springs out with the owner watching anxiously, since he wasn't convinced that the cables should be allowed to have slack. Until he flew it. Big
The rudder self-centers in flight. You can pull the pedals up with your toes while flying, the cables will be slack in the interior, air loads will continue to hold the rudder centered. That's how it is.