Any A class is capable of out pointing an F18 or an F20 (with advantage -VMG) by more than a "few" degrees simply by its hull shape, rig configuration, weight (or lack there of) etc, etc, regardless of the centre boards being canted or otherwise? So a comparison to these other classes cannot really be taken as any sort of “conclusive” result?
The only comparison would be A class to A class, - one with and one without (canted boards).
Hydrofoils by the way are of an asymmetrical profile generating lift only in one direction, due to their shape and their movement through the water, the centre/dagger boards referred to as “cantered or not cantered” are of a symmetrical profile that will generate lift on either side of the foil, depending on their angle of attack relative to their direction through the water.