You might contact Don Proul at Foss Foam - Fossfoam@aol.com. They have redesigned the E-27 rudder. I don't know anyone sailing with it but Don can tell you what it might do for you. If I remember correctly he said it was about $900.00.
I had Don do a rebuild on my 32 using the old metal and it cost around 800. this was based on a larger design and it made a huge improvement when going downwind. I'm not sure if the 27 rudder is sized accordlingly, but the 32 would have very little wetted surface when the boat heeled over.
shaun