And for a while, Agfa sold their color film as "24 + 3" -- not 27, but "24 + 3."
I think Foma might have as well, my friend John in England did not like the 24+3 as the processing people charged a lot more for anything more than 24.
I tried bulk loading a bit longer than 36, and it sometimes caused scratching on the base.
First bulk film I had was Tri X, but I had no loader, so the first roll was loaded all by hand, I used to feed the film on to a developing reel to make sure it was not too long. Kodak cartridges had pop off ends. Last pop off ends I have seen were Foma a few years back.
I see Tom A in his You Tube video on bulk loading uses a basic length measurement system. ;-)
I also recall the first cartridges you could buy loaded, post dated the first Leica Cameras, so I assume the design of the cartridges was related to the camera. Am not sure when the loading tongues were shortened, making it necessary to trim film leaders for loading in SM Leicas.
Kodak used paper "cans" and later really nice metal screw cans in various colors to denote the film types. Agfa cans were sealed with tape, and the cartridges were closed differently than the Kodak Snap Ends.
I have a feeling more bulk film will be in our futures.
Regards, John