Ipe or osage is the wood you need for such a narrow bow. If you want a long ELB, sinew won't work. The narrowest bow I've made was a maple backed osage, 1" at grip. 72" NTN, 45#. If you have the right piece of wood, a selfbow is fine, but if it was me, I'd back it with something, especially if it's a board.
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