Neal,

The upper battens on "SPITFIRE" go upward. You are right in that they
reduce twist. In this case Twist to the horizontal.

Neal, I sail full battens and I can induce twist as well as you can and
keep the Roach section in shape as it twists.

That is what battens are for, to maintain sail shape.

Hope its warm by you. To cold here to get the aroma of a good fart.

Ole Thom