Those fluorescent fixtures with the 2" ko's at dead center tend to really irritate me when I am planning to directly enter the fixture,oops luminaire, with a romex cable at the center of the fixture. I don't see the fixture until trim, so didn't plan for it to have such a big ko right where I want to send my wire into the fixture. On some of the ones supplied to me, trying to unibit a1/2" ko into the 2' ko is a joke, it will practically fall out in its entirety.
it is going to be really hard to learn how to say "luminaire"all the time, or however it is spelled. I was just learning how to spell "fixture "correctly. Kind of reminds me of when "grounded" circuit conductors took over for" neutrals".
I thought I just saw in one of the trade magazines, a new plastic connector that goes on the inside of the box. I believe it was made for old work and I think that it was listed and labeled for use. I have to go back and see if I can find it.