I think somewhere in a corner of Bobby Muller's boatyard closet in Annapolis is a rudder I had modified which would probably be exactly what you're looking for. Email me directly if you'd be interested in buying it.
Bonnie Schloss (Bearaway@erols.com)

I've been cruising my J-30 with modified, balanced rudder for 3 years, and love it!
Someday, I hope to class race the boat, but as long as the balanced rudder is illegal, I won't be class racing. I suppose, someday, I'll purchase the legal rudder. Jeff Moore (Roo)

Jeff: I just got an old rudder which I plan to modify this winter. How was your rudder modified. Did you cut away at the top, modify the shape below the water line or something else? Any suggestions on do's or don'ts?. Thanks for the info, Mike #21