Baltic,

Very good idea. I will give you a call later.

Wouter,

I agree with you for upwind courses. But if I am on a reach, drag doesn't matter, only lift until you can't hold the heeling moment any more. And you get the maximum lift out of a sail or wing, if you bring all parts of it close to stall at the same time. And exactly for this condition I want (or I hope at least) to set up the sail as well. I can always open my leech with the downhaul for the upwind leg.
Maybe it is not possible to stall the top with a square head sail + wing mast and without jib (which protects the lower and middle part of th emain from stalling) <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />, but before I make early assumptions I will listen if you guys can stall the top of a cat rigged square headed and wing masted boat.

Cheers,

Klaus