my opinion is to make oaks wide. the shorter you plan to make it the wider it should be, or the more stress you plan to put it under the wider it should be. I dont think there are any set dimensions, but i like to make my limbs about 2 inches wide at the fades. And about 3/8 inches at the tips. whats in between is up to you. if you want a 50 lber then you should aim for a shorter bow like 64 inches and keep the limbs 2 inches wide for around half the limb maybe more, and then taper to the tips, which should be around 1/2 inch. the handle is up to you, you can make it super narrow but really deep or you could make it really wide and not as deep, or you can find a balance. 1-1 1/4 inches is a good sized, then just leave it deep until you need to have the handle bending, if you dont want the handle bending you can make the bow a bit longer and have a static handle. Granted, every stat i gave you is relative, none of it is going to be exact, so just go with what seems about right, after your first one, observe what your bow looks like. if it took set, ask yourself why. did you have it on the tree for to long? were your limbs to thin or to narrow? was the design a bad design for the wood? figure out what you did "wrong" (not really wrong just maybe not what you were looking for.) and then you can improve on it the next time. keep improving until your pumping bows that are amazing and seem perfect. If it helps you can keep a bow journal, in it you can write down findings and experiments and what works and what doesnt, and what to watch for and what to expect. Hope this helps