EUREKA ! take the paddle shaft(s) over to MACHINE SHOP. Ask how much for 2 aluminum tubes 0f say 5" to SLIP fit into CF or Al shafts already attached to your blades. If you have the $$, bring your mail order hardwood dowel for an ID 5" fit.
Chop a hole into dowel for the stock spring/button latch. Gflex and screw into dowel. Epox the dowel end grains, prophylactic bothe dowel ends, Gflex ID 5" tube and dowel then fit together