You know, if you really can not chase a ring around a knot to save your life, then the most obvious answer is dont. Sapwood does perfectly fine as a back. Many say its no good, many say it is. Those who say it is can prove it with bows they made. Those who say it isnt prove it with broken bows they made. But by the same token, many used to say boards couldnt make a bow, and many said they can, and proved it likewise. If your bow is not successful, it wont be because of the back I promise. Give up trading these nice staves and ( well its up to you, but I would keep em ) make a nice recurve from the one on the right, and the twisty one is a nice character bow. Oh, and move on over to the bows thread, and post over there about them and what bow you wanna make of them.