For hardwoods, use a craft heat gun, and heat the shaft up so that it is hot, but not scortched and not burnt. The shaft will limber up like kind of like a noodle. So heat the spot where the bend is, and straighten when hot, then work on the next spot. It takes a little time to heat the shafts each time but not too bad. Make sure you seal them when cool shortly after straightening them, because they do take on moisture rather quickly. Doing it in the winter is ideal, when humidity is low.
I just bougt ash shafts from Kzoo, 2 dz. I decided to foot cedar rather than shoot all hardwood. I use the arrow fix tool and expoxy 2 3/4 inches to the front of my cedars. So I straighten my cedars, and use about 2 ash shafts for a dz cedars as footings. I had really bad luck with real footings, so I tried this arrow fix tool and am much happier with the strength of the arrow.