Hi Mike,
First let's get our feet on the ground.
The subject is as old as dirt.
Gybing a centerboard does not change the lift. The side force that a centerboard must generate is equal to the side force from the sails. These forces are equal and opposite reguardless of CB gybing angle. A gybing CB might change the path of a hull through the water, the sideslip angle of the hull, but it will not change the sideforce. Let's say we want to allow a CB that is supported for 24 inches in the CB trunk to gybe 3 degrees. How much trunk width are we talking about? The sin of 3 degrees times 24 inches equals 1.1 inches. If the board is 1.0 inches thick itself in the trunk and we want the board to be able to gybe plus and minus 3 degrees, that means the front of the CB trunk at the keel must be 3.2 inches wide. Wow, what a hole, what a wide slot, hard to seal, probably much water pumping going on in the trunk and that is negative horsepower.
Dream On,
Bill