Wayne you could try this on one leaf. When its picked and after its had a week or two of drying dip it in a fairly strong sugar solution. Sugar is hygroscopic and that should still allow the leaf to dry out enough to smoke but retain a smidgin of moisture enough to prevent it from becoming brittle.
I am a smoker and when I first came to the US I had a hard time adapting to American cigarettes which seemed harsh and 'dry' compared to British ones. What gives, they both use Virginia tobacco? Apparently English tobacco was sugar cured, so I thought, maybe that's the answer.
Never tried growing tobacco but I probably will have to soon. Will have to figure out what the secret is to Captain Blacks flavour, its getting too expensive these days.
Just found this at the bottom of this short article on Cavendish
http://en.wikipedia.org/wiki/Cavendish_tobacco