Ryan, the thickness of the limbs just depends on the individual piece of wood, the design, width, etc. The limbs will wind up however thick they have to be to bend the way you want them to at the weight you want. With selfbows, the thickness of two bows made from the same kind of wood may vary considerably at the same drawweight. Each stave is different, and may have knots, stiff spots, reflex, deflex, or any number of things going on-so the final thickness is determined by how much wood you have to take off to make it bend right. A good general starting point with whitewoods is about 3/4" thick at the fades, 5/8" at midlimb, and 1/2" thick at the tips. This will usually leave you with a stave that's still stiff and heavy, but will bend some when you push it. After making a few and getting the feel of the wood, you can cut those dimensions down 1/8" or so and be closer to floor tiller right off the bat. It's usually better to start too thick than too thin, though.
