I have the only tip you'll need. Don't bother. It not only probably impossible because there not a clear color definition, but it's not at all necessary.
Just try to limit the amount of grain violation.
My first hickory bow has been shooting for years, 55#@28", 62" long, it's back is the outside of the log, but it literally has hatchet marks up and down the back and no problems. I was stupid then. But hickory is really strong and can take it.
If the grain on the back of e stave looks like it would be good for a backing strip, then it is good enough for the back of a self bow. Actually hickory is so much stronger as a backing than a belly, at a hickory self bow can really get away with quite a bit.
Good luck. Post pictures if you want to know if the back of the stave looks good.