I've made the string and dowel model, but I want to make sure that I'm not missing a critical concept or spirit of design. The crux of my question is that if the sling point is at 50%, and the downhaul is at 33%, the sail isn't just hanging.  There's got to be tensions in there somewhere. 

1) When the model is hanging loosely from the sling point (approximately 50% of the chord), should each batten balance roughly horizontally?

2) Is it then the the combination Downhaul/Batten Parrel that establish the peaking and 10 degree batten angle?  Or perhaps something like a combination Throat Hauling Parrel and Downhauls ?  If that's the case, then is it correct that the running tensions in the system all fall to these parrels/downhauls to keep sail shape?  I'd think that at the very least, they have to take the weight of 67% of the bottom sail wanting to slip forward.