@John RB - I was able to do more low level testing tonight and everything worked great with properly configured & loaded double-Michoacán hitches in the JRB Climbing System. I tied the 5-wrap configuration for each half of the double-Michoacán hitches today. The hitches held great and it was easy to overcome the friction to break them when I was ready to rappel. Tending them on the way down while rappelling on my ATC device was also easy. (It was night & day vs. the improperly configured & loaded hitches I was using two nights ago.)
My climbing rope was the Mammut 8mm Alpine dry (dynamic) rope.
I tested hitches made from Teufelberger 6mm Ocean Vectran cord first. Their performance was satisfactory and I would not hesitate to use that cord if high strength is a priority. It always held, but sometimes slid down an inch or two before it set. I think that with a little more attention to the initial dressing of the constriction, that can be eliminated.
I tested hitches made from Sterling 6mm TRC cord next. Their performance was better - they always held, and never slid down at all before they set. And they were a little easier to break when I was set up to rappel on my ATC.
I look forward to comparing the performance of the Sterling 6mm Accessory Cord when I receive it, but for now I’m good to go with the TRC.
Thank you very much for your published video content, your help, and your attention to this thread!