I agree with all that. Those a basically springs. If I could find a cheap source for the right sized couplers I would include them in a heart beat, but at about $8 in bulk I’ll stick with a printed one.
Rigid is better, spider couplers would be best. The one you listed is not good, it is an 8mm, we use a 5/16″ I know they are close but they are not close enough in my opinion. You will need to shim it with something like a soda can piece of metal. I have wrapped literally hundreds of these for a previous company I worked for to get rid of the wobbles that the off center clamp creates.
“the uglies” your wife sounds awesome! Next time I break something I am sure that will pop in my head. hahaha