I use a cheater method and it works great: Just one lam of glass, applied to the back of a standard Osage board (about 3/4" x 2" x 70") as if it were bamboo or hickory backing, using C clamps and a reflex-deflex form cut from a 2x8. Use epoxy of course rather than glue. No heat box necessary; just put in a warm place for a few days. I then use a bandsaw to cut the basic limb tapers and start tillering the Osage like I would an all-wood bow, until I get close to the weight I want. If you get it too weak you can always shorten the limbs to get back up to weight. None of the bows I've made this way, so far, have delaminated or broken or gotten weaker. Have fun, dave