Steve, Dual head sails - on twin head stays - is used for Trade wind sailing.
From the Canarie Islands to Barbados; or Transpacific. i.e., it is a solution for a very specific sailing problem; running for days and days on long passages.
I doubt that any owner of an M15 is contemplating such a trip. For any sailing that I've done with the M15, I can't think of any situation where I'd want to go to the complication of dual head stays. It sure isn't worth the hassle for a 1 hour run! Stay with the original set-up and if you really have to have a new toy, then get a genniker and enjoy that. Connie ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/web/.