Twenty to twenty-five degrees of twist in a stave is chump change. Stop worrying yer pretty little head over this and get to stripping the bark and sealing the backs of the wood. It's gonna be some time to get that hickory cured out, expect to wait at least a year for every inch of thickness.
When it comes time to making bows outa this wood, get your stave worked down to the point that you can start floor tillering and then steam the sections of limb you see the most twist, and untwist it! You can also use dry heat on cured hickory, but my preference is steam. Hickory is one of the easier woods to manipulate, you can take twist out, take out kinks, bends, and warp, too. You can add recurves and bend the handles until the tips line up. In this, hickory is a very forgiving wood.
It is absolutely unforgiving when it comes to humidity. A hint of humidity and hickory stops being a quick performing bow wood and becomes a sloppy floppy mess.
