I just did the same thing, I bought rawhide bones about 16 inches long. I sorted through the pile and got the thinnest, most-transparent ones in there. Soaked them until I could undo the knots, soaked them some more, cut them into strips, stretched them by pulling them back and forth over a door opening, then soaked them some more. I got strips over 3' long, and I think stretching them aligns the fibers lengthwise (like stretched rawhide string) for extra strength and less thickness. I sized the back of my bow with knox, soaked one side of the rawhide with knox, and tied one end to a tip of the bow before wrapping with string while holding tension on the free end for maximum tightness. Seems to have worked really well, and now I intend to file or sand it down until the pressed-in string grooves disappear. Hope there's a tip or two in this ramble you can use!