I was thinking of putting a couple large plastic garbage cans off the bow, sunk a few feet below the surface. That will provide some inertia and water resistance forward where it is needed to let the boat rotate (yaw) at more forward point than the keel is providing.
Other than moving the wet rotation point forward, the other thing to do is to move the wind pressure aft, like with a riding sail. There's a guy on eBay that sells them every couple weeks for $49. (I've asked him about making a bigger one for larger boats. He's looking into it.)
One question is "How big does the anchor sail need to be?" My thoughts are that it needs to be a bit bigger than you would think, but that's based on little or no information. It might pay to get an old storm jib and attach it to your backstay to see if it has enough affect. The cut will be wrong, since anchor sails should be flat, but it would tell you something.
Great minds discuss ideas;
Average minds discuss events;
Small minds discuss people.
The best minds discuss sailing. I don't know why. It's a mystery!