I've been asked to kiln dry and large black walnut slab, approx. 12' x 30-48" (90bf) that's currently 27-30%. I've been told that it's not a good idea to put wet wood (>25%) into the kiln as it's prone to excessive cracking, warping and even case hardening. What's been others experience with black walnut. Is it stable enough to chance it? I've explained all the risks to the guy but he still wants to have it kiln dried.