Your tailwheel can't be free floating. Just the torque of the engine will send you to one side or the other. A skid doesn't work at all in grass, and marginally on pavement.You can attach your tailwheel to the rudder with a dual spring setup from DuBro. It uses two control horns on the rudder and then two springs go down to the tailwheel, which has a bracket. Make sure you have the correct toe-in on the front wheels, also. If all else fails, move the main gear back and add a nose wheel.