Jack - I've not sawed any yet but what little I have seen was cut at 4/4 and it cupped / twisted / bowed and end grain split pretty bad after it air dried. When drying it you might want to consider putting a bunch of weight on top of the stack or better yet ratchet the stack down good and tight with some wide ratchet straps, the ones rated for 10,000 lbs. Come back every so often and gorilla torc the straps down to keep a bunch of pressure on the stack as it dries. I'm sure quarter sawing would have help the persimmon I saw, it was all flat sawn.
Thanks