I was thinking in the same line you were, Mary. All I'm saying is that if you move a, say, 50-lb rig, from the center of the boat to the windward hull, you have accomplished the same thing as having a child crew moving the same way. Righting Moment is increased: clearly it will now take more force from the sails to fly that windward hull, because you now have the weight of the rig to lift. On the other hand, Heeling Moment, ALL ELSE EQUAL, is the same. For a given wind strength and angle, a given rig will always produce the same heeling moment and the same amount of drive (assuming everything else is the same of course.) In the same conditions in which the boat was just flying a hull, with the rig in the middle, it no longer is. Now, the equilibrium Heeling Moment, when the hull begins to fly, must be exactly the same as Righting Moment, but both forces will be greater than they were when the rig was in the center of the boat. Of course, don't try to tack!
hope this helps