I've had bad luck with walnut too,but it is highly elastic per its mass,and so light it can make a fast bow. One of my faster bows( not really a bow tho) was a trapped hickory backed all heartwood walnut 68" ntn 30/70 ratio lever bow. It was smooth pulling n smoking fast,but after 50 shots it had fretted..I was bummed cus it also looked very attractive..also had a problem with a stave,but it didn't fret,but its tiller went out of whack after shooting in,fixed it,then the other limb went out of whack even after tiller was good and corrected,and so its weight went too low for me,so I tried to break it and see how far the stuff would bend..holy smokes that stuff can take a bend and not break..I bent it 90 degrees and it still didn't break or fret yet it was narrower than the trapped hickory backed walnut,so I never broke it n set it in the "corner" as a reminder. One of these days ill give it a whirl again...funny you post this cus Pearl n I were mockingly talking about walnut earlier today..lol.
How wide is it? Good job...you've done something I haven't been able to do yet..lol.