1 and 3/4" wide is plenty for black locust. I made one that weight and it is fast for the draw weight. I really like working with it, but like osage, finding a good straight stave without too much "character" is sometimes challenging. I am finishing another black locust D bow now, 64" long, 55# at 28" is my target, and I am getting this from a stave 1 and 5/8" wide, with gently reflexed tips.
For every 8-10" diameter black locust log I try to get staves from, I usually get one good stave, one or maybe two OK staves, and have to make firewood of the rest. I have zero luck getting good piggyback staves from larger black locust logs. It always runs out on me, and I think that is a good property. It means adhesion between growth rings is really strong.
Black locust bends with heat pretty well if you need to recurve or straighten it. But if you are recurving, do it while the wood is still a little thick because I sometimes get a little "crushing" on the back of the bow where the recurve is. It does not seem to affect strength but for appearances you might want to take it down another ring.