It is true that a steerable tailwheel is preferable, but a caster tailwheel works fine for all practical purposes--just gun the engine to put propblast on the rudder when you want to turn. My solution is to fix the tailwheel tiller to the rudder by slipping a piece of fuel tubing over the tiller, then gooping the fuel line to the bottom edge of the rudder. This allows any tailwheel shocks to be absorbed without overstressing your rudder servo. This approach works well with the Dubro tailwheel, which is lightweight and reasonably priced. Try to line up the vertical axis of the tailwheel wire with the rudder hinge line--but if you're off a bit, the tiller will just slide around inside the fuel tubing.