In the anti-parallel configuration, although roll control is lost, control about other axes still works well (in contrast to the situation with saturation). An unwanted left yaw can be dealt with by storing some "up" angular momentum, which is easily done by tilting both rotor spin axes slightly up by equal amounts. Since their fore and aft components will still be equal and opposite, there is no change in fore-and-aft angular momentum (it will still be zero) and therefore no unwanted roll. In fact the situation will be improved, because the rotor axes are no longer quite anti-parallel and some roll control will be restored.