Thanks for the info. While perhaps workable in an emergency, I don't intend to operate in a "continual state of emergency". That is, I either convert a batch of cars to Sergents, or I don't.
My first batch conversion was for most of my Bethgon's, and their locomotives. That's where the dummy couplers came in handy, since I run them as a unit train.
Lately, I have started converting my more modern intermodal cars. This will now have to stop.
I had been planning to convert my passenger cars to Sergents, also. This now won't commence.
Once converted, the above rolling stock (and their locomotives) will not interact with Kadee equipped rolling stock. So the need to couple Sergents and other couplers is near zero.
Incidentally, I use only the non-shelfed type E's; as I want to be able to uncouple "vertically", if I wish. Inauthentic, admittedly. But, then, I can use my choice of 4 shank lengths if I can get them.