Remeber that the extra bouyancy should not be used during normal sailing, it is just as an safety margin when you sail the boat bad! Using the extra bouyancy gives you loads of drag compared to using the normal water line.

The new A-cat shape requires that you sail the boat correctly. You have a designed water line, sail the boat that way. If you get the bow to much down, move back and depower the top of the sail and get the boat back to normal position. No one sail the A-cat bow down when going downwind! You might need the non existing extra bouyancy in some extreme conditions, but how often does that occur? The A-cat is a racer and is designed for upwind-down wind racing during "normal" conditions.

Weight
Is a heavier boat is more resistant to pitch poling than a heavier one?!
Take an M20 sailing downwind, add 80 kg in the middle of the tramp or maybe a bit above to compensate for a heavier mast and rig. Is that better or not?
The righting torque for pitch poling divided by total weigh of the boat including crew is always better in a lighter boat.

/hakan