I never used HL. DLH, locust gives off moisture really easily. You are on the right track. Let it air dry as much as possible w/o heat. If one is not careful in drying it many drying cracks will result. Did you seal the ends? I've made BL sapling bows with sapwood backs and in fact, my first bow successful bow was from a sapling of BL. It functions best with a heartwood back but of there is not enough of it leave a sapwood back. Do get as close as you can to the heartwood though. You may catch it close to becoming heartwood. I learned bow making on the stuff. I have access here in my yard and used a lot of it many years ago when I started. Generally, leave it wider and longer than most other woods. What is your draw length? Those saplings seem to have a pretty hefty crown so be sure to leave them a couple inches longer. I haven't had many BL staves chrysal. I've had better luck with it than ash. BL was a favorite wood among the Native Americans in NH... that and hickory. I think its chrysalling reputation is unearned. I suspect that Northern black locust is better than its southern counterpart though. Locust is a pretty neat tree. Like peas and beans it takes nitrogen from the air and brings it into the soil. It is a legume. I like it but haven't made a BL bow in awhile. Getting older so I don't cut as much. But I cut some last fall and making a bow from it may become the subject of a magazine article for PA. We'll see. BTW the Native Americans preferred the longer narrower designs n hickory and I bet BL too. Have fun. Jawge