Hi Jami
It will be interesting to read your report when you have accumulated more miles, in varying conditions. Your few words about the lee and weather helm, strengthen my belief that the balance issues is hull-related rather than related to (any ) rigs.
I begin to wonder if boats with such weather helm issues should rather be rigged as yawls, so weather helm can be trimmed out, just by easing the mizzen sheet.
As for the use of the Johanna-sheeting with its strong anti-twist, I am not so sure. This was specifically meant for the Hasler-McLeod style sail with a tall yard angle and full-length yard and top battens. It may well be that this kind of sheet will produce ‘negative’ twist on your rig.
Anyway, keep up the good work!
Arne