" I did find a few places in it where the grain in the growth rings seems to switch direction. It was all about 1/2 to 3/4" deeper than the ring i established for the back. Makes the grain on the belly look strange but i think most of that will be gone when finished.....if it survives"
Do you mean by this that the grain in an older growth ring dioesn't follow your snakes in your chased ring, so the two are parallel back to front, but skewed side to side?
If so, I'm sure angle of violation matters, but I would bet money you'll be ok 90% of the time. I have seen this in black locust, and the only major problem was that it wanted to tear out in long gouges as I split and roughed it out, so I was worried about having enough width on the belly. but it should hold, taking the compression, unless it's wildly off.
That is a cool as heck stave.