A couple of Weather helm hints
At what wind speeds do you begin to get pronounced weather helm? I owned a tall rig C28 for several years on San Francisco Bay and we were constantly fighting weather helm and heeling. Drop your traveller all the way. You are getting most of your drive from the genny and from the back of the main so let the main's leading edge develop a luff curl. When the winds were in the mid teens we would tighten all the main controls - vang, outhaul, halyard, cunningham. Our purpose was to flatten the sail as much as possible. Shortly there after we'd have the first reef in. It may look like you are sailing with training wheels, but you will actually go a lot faster. The other thing you might check out is your mast rake with a plumb bob. If your rake is in excess of 5" at the gooseneck (check your manual) then you have too much rake which is causing your problem.