Well, referring to what Steve said, I have no experience with a hackberry warbow so I can't give any real advice on that, but I can with longbows up to 70# - 75# or so. I just make it a typical white wood d cross section, which I guess is just a little wider d section than an osage/yew/locust bow. But that is just me, it could probably take a narrower section without too much harm. Hackberry is physically light, so you can take advantage of a longer bow if you want, to get less set or a smoother draw without hurting speed much at all. In other words, since the wood is so light, a 76" bow isn't going to shoot much worse if any compared to a 72" bow, because the wood is so light to begin with, but the 76" bow will be less stressed from being longer and may take less set than a 72" bow. A trait that I have noticed is the bow will be fatter then even most white woods for the draw weight of the bow, so my advice is to start out testing it early on to see if it is bending or not, depending on what draw weight of a bow you are trying to get. Other than that nothing is different than any other longbow.