Mike, I haven't tried it myself, but if I were working that stave, I think I'd run a taut string along the back side of the bow, tip to tip. Measure from the string an equal distance to each end of the handle. Draw a line between marks and rasp off what's beyond the line. Then your handle will line up with the bow and it should be balanced. If your handle is too thin you can glue on another piece of wood. Then again, maybe ideas like this are why I don't always succeed when I'm working a difficult stave.