I have made a few BW self bows. Just peel the bark and make the bow with the sapwood. You will probably get a bit of heartwood in the handle. I would make it overbuilt as per Comstock...68" long, 1 3/4" to 2" wide at the fades and out half the limb(or more) and taper to 3/8" tips. You can easily get a bow in the 50# to 55# range and maybe more. Pat