My favorite design for all my board bows is 67-70" long; limbs 1 1/2-2 in wide (depending on the type of wood and the board) to past mid limb then tapering to 1/2 in nocks. For me, this design is stable, durable, and easy to tiller, and I like the looks of it. But I like things simple. I will post some pictures of the one I am working on now when I finish it. I have made board bows out of red oak, white oak, hickory, cherry, hard maple, and ipe.