I know it's hard to wait on, and even harder to get sometimes, but well seasoned wood will give you less trouble, than say, well dried/fresh wood Living Waters. Especially when using hickory. Try heat treating the bellies of your hickory bows if using less than well seasoned wood. Tempering mimics seasoning to a certain extent.
As far as hitting the weight you want, getting a short string on as soon as possible, get the bow's profile where you want it, and then draw and set draw length and weight by hand. More hands on as you near the final tillering stage is much more effective than by using a tillering tree IMHO.
Okie, about any nut tree will probably work fine for a bow. Give 'em a try....Art