Brian,

The H17 guys down here are using a very simple system of a long bunji that is tied from each of the forestay / deck attachment points to the rotator bar by way of a carabiner. This forces positive rotation on the mast. During a tack/gybe, the mast is pushed through center by the sails and and the new windward bunji, while still attached, is at less of an angle with less mechanical advantage since the rotator bar is sticking way out to leeward. I'm not sure I described that well.