I would bet that you could indeed make full deflection of the cyclic during shut down either with hydraulics or not but doing so while the blades are still spinning is a tougher deal. You would have to make this maneuver contingent upon a very low rotor rpm as you run the risk of a mast moment exceedance otherwise. I haven't played with the cyclic on shut down (I'm not a pilot either) so there may be a windo of time when tip speed is low enough and pump speed is high enough to pull this off. I'm not sure exactly what you are trying to accomplish but if it is simply to move the cyclic to the stop in one direction then it may be just as easy to do so without hydraulics after rotor stop. I wouldn't want to fly it this way but you can sure move the controls full travel with a little effort.
Good Luck
Max