The OP's question was about carry guns in "rotation," but the thread has wandered off.
My take: If you are carrying a firearm for SD, then you should be able to operate it without having to consciously think about how it works. Kind of like picking up a retractable pen and automatically thumbing the "action" then putting it to paper. Being able to shoot 1" groups at 25 yards is virtually moot because almost nobody will ever take a legitimate SD shot at 25 yards.
Put simply, operating an SD handgun involves clearing the holster (something that many ranges don't allow, but which we can practice at home), getting the front sight on target (something the shooter may not have time to consciously think about), switching off the safety if it has one and it was engaged (an option each shooter has to make), pressing the trigger (or, if the situation swiftly changes, deciding not to press the trigger), and putting put two or three rounds into a paper plate within a couple of seconds.
If a person can do this consistently, I'd say he or she is good enough. If he or she can do the above with any of a dozen different guns in rotation, that's still good enough.