Mate, Know of any of the pointy end of the Interntional Moth class that doesnt have at rudder foils? Even those who havent made the move to "flying" International Moths.. Ok they may not be "professional" sailors but I suspect they are possibly some of the most skilled sailors professional or Am around..

As for I 14s..
I believe your misunderstanding why International 14s have rudder foils.. Its not to reduce nose diving although that may be a beneficial side benefit.. The reason Bieker started the I14 rudder foil tren is to reduce the aft wave and hence make the water "believe" the hull was 16 not 14 foot.. So trimming of the foil is required for the incline of the hull to the water.. As Im sure your aware I14s sail flat upwind and a slightly nose up position downhill.. As for benefits Bieker suggests med to light air will show the BI14 rudder theory.. Not when the I 14 is airborne..
This is evident in the positioning of the I 14 rudder foil.. Bs foils are above half way up the rudder not at the base like the Moths or cats..

Just a few thoughts..

S