So, I've been thinking about this construction. If the handle is one-piece, how thin the wall of the rings would need to be given that the leather is fairly thin and you would want a flush transition from leather to ring to leather. Perhaps the handle is three pieces so that you can have a reduced diameter at each ring position to hold the rings and an appropriate larger diameter for the wrap area? Thread them all together to lock up the rings? This would be a fun project to play around with. I guess this gets easier with a full core, it would just have three handle pieces..