There has been some testing done over the years on wax.

Chemical and piping firms looked at coating the inside of pipes with wax, because it pays off if it reduces the power needed to pump liquid. The result was a waxed surface at a given surface roughness was the same as a unwaxed surface.

There have been a couple of student studies on the effect of wax or polish on boats. One was a link from Mad For Sailing, one I saw at a conference and I know I have read at least one other. The result the better the finish, the lower the drag and the better the flow stays attached (very important for rudders). There was a big improvement between 400 grit and 1000 grit. The difference between highly polished wax and unwaxed surfaces was minimal with a slight edge toward waxed surfaces.

If any of you are students, in need of a project for a lab, especially if you have access to a flow tank, this would be a pretty good research project. You could probably publish in at least one of the major sail magazines.