consider the cellulose kitchen sponge as it dries. It can go from sopping wet to sorta dry without distortion or shrinkage. after the "free water" ( the water you can wring out), has evaporated, shrinkage begins.
even thicknesses help consistency in drying
in very dry conditions I have found that not only the ends need to be sealed, but the stave needs to be sealed on all sides for a few inches from the end
your staves may need to be moved to more humid or cooler conditions when the free water has left, monitor your stash