I have not read or heard too much into the I14 rudders, but from everything I have heard from the AUS fleet, Stuart is correct.

I believe the biggest gains were made upwinf where the foils tricked the boat into behaving like it had more waterline length by reducing stern wake.

On the downwing the foils are left pretty neutral or maybe a slight hint of raking them back. Up wind the raked the rudder forward. This also helped lift the transom out of the water.

Reduced pitching and nosedives was just a perk to the theory.