I used some left over pieces of Carbon Fiber arrow shafts instead of the dowels supplied and added some ply to the former. I made some inserts out of aluminum tube so the carbon shafts seat into aluminum instead of wood. Good snug fit and no problems. I had recovered my Ultra stick (.60) so I made a ply bracket to fit over the wing spars and the Carbon shafts seat in this bracket and are not just epoxied into the leading edge.