The ideal tail rotor:
Location - Close to the roll centerline of the aircraft so that the normal thrust changes that stabilize the yaw axis in forward flight do not produce any roll BUT the rotor must be protected from ground contact during the landing flare
Rotation - bottom blade forward, so that the blade moves into the natural outflow from the rotor in low hovers, thus gaining some speed and effectiveness
Distance from fin - about 1/3 diameter or more so that the fin does not block flow
Direction of thrust - toward fin (pusher prop) so that the high velocity downwash is not directed against the fin, making the rotor more efficient
Thrust - large enough to completely overcome main rotor torque, so that typical small variations in thrust caused by main rotor wash entry do not cause loss of control (mislabeled LTE)