I don't have any of the standard length, but don't the cartos have to have a flange?
No, they do not have to have a flange.
Smoktech came up with the flange idea to prevent a tank from sliding on the carto toward the battery. It does not prevent a tank from sliding off the carto away from the battery. It's a nice idea for the flange, but it is not necessary. tanks tend to settle and grip the carto a day or so after they have been filled.
It's just common sense to pick your device up by the battery, and not by the tank. Follow this practice and you will have no spills. Smoktech is the only carto manufacturer who utilizes the flange.
Non-flanged cartos work just as well in tanks, including Smoktech tanks. I use primarily Ikenvape cartos (no flange) in all of my tanks, and I have not had a tank slide off my mod ever, because I've made a practice of only picking up my mod by the battery.