Just a thought.
I have been looking at a photo of an atalanta sailing hard on the wind with one keel box totally out of the water.
I wonder if she would be faster with tha windward keel fully raised? My thinking is that the keel weighs more out of the water – so lifting it would increase the righting moment, and reduce the wetted surface area.
Would that balance the loss of keel area stopping sideways motion?