You have several options. First, cut 3" off each limb and make a 60" bow. I have a stiff handled unbacked 60" osage bow that has a little set but shoots great. It is hard to bend the limb 3" from the end, you're probably OK there. Second, make the limb even at that point through the tip, do the same to the other end and add a belly lam to the thin spots. Similarly you could add a long tip overlay. And of course, lastly you could make a bendy handle bow of 56". Much better to make than kind of booboo 6" from the tip. Takes a lot more force to bend the limb at 6" from the tip than 6" from the handle.
Good luck, I'll quit hijacking.
George