The octogenarians over at steamradio, a multihull forum, usually only worship Kelsall and swap stories, but once in a while something great leaks through. This time a Tom Speer paper. Tom sailed with me on the Geko once. It was gusting to one knot and glassy calm water. He did have all his man overboard gear on at all times. Unlike someone else.
http://www.tspeer.com/Wingmasts/teardropPaper.htm
Over the years I talked to 2 people that have teardrops rotating masts and one multi-builder. The advantages are when they are thick (over a foot) because you can sail slowly without a sail in most conditions (7kn+). You can go eliptical or circle and the difference is going to be negligible with a sail.
This is hearsay.