So I’m an archer not an Atlatl guy. But since it is just a stick that throws a stick, I cut a branch, carved it up, then promptly obsessed about finding good dart material. For Texas, broad leaf ligustrum is the solution. It grows straight after copicing. I have a mott of Ligustrum in my yard so I harvested some 1/2″ poles 5 feet long and made the darts.