If you don't get your question answered here, try posting it on the sailboat section of http://boatdesign.net/forums/. There is a chap who frequents that forum called Tom Speer who seems quite knowledgable on foils and always gives a good answer.

If anyone has ever found any references to the best shape for a foil at the surface boundary I would like to see it. I have heard lots of people like Wouter say that traditional foils are not good, but have yet to find anyone to say what is good. Perhaps I will post that one my self!