My hubby also attempted to make me a spindle for plying, my other spindle was giving me problems when plying my singles. When it gets full the yarn keeps falling off the hook. The bigger whorl did help with that problem but the spindle was super unbalanced. So its back to the drawing board.
I'm currently testing out some patterns to possibly use my handspun yarn. I'm using commercial yarns of similar weight and texture because I don't want to have to rip out so much with my handspun.