What ever came of these ?
I remember playing with some I made from JB Weld and putting a 2 degree angle on it to match the wedge. I gained about a .5 to .75 mph but lost about 50 rpm.

I just purchased one on ebay for like 20 dollars. Figured I'd give it a shot again. If it's not noticable I might just shave it down so it has the same angle as my wedge.

..just makes since for water flow.