Hi Nick and all.
The postings are very illuminating. I agree that the Woodie is most stable at 90 degrees and the World has inherent problems causing inevitable inversion. These inherent problems seem to be caused by the double floor and the buoyancy in the sides of the boat which change the C.G. and C.B. at 90 degrees.
Might it be possible to use the double floor to advantage? Could two chambers be built within the floor either side of the centre of the boat to be filled with water ballast? In sea cruising and family day sailing mode the filled chambers would increase stability. In 90 degree capsize mode the boat might not invert so readily. However, it should be noted that should the boat invert then righting, due to extra weight, would be even more problematic.
When racing or cruising in light winds the chambers would be empty keeping the boat still in class. The water could be pumped out prior to recovery to dry land when in cruising mode.