Supporting a lens with a screw-in connector is really going to slow down changing lenses. I have always just cradled my heavy lenses (up to 8 lbs.) with a simple device like this. It is easy to change lenses and quickly reposition or remove the cradle. I raise the cradle up just to the point where it starts to lift the lens and then lock it off. I routinely carry my cameras over very rough terrain with a lot of movement and have never had a problem with the cradle method.
Zacuto came out with a support system many years ago. But, honestly, the Canon CN-E primes aren’t really heavy enough, or long enough(to produce high levels of torque) to warrant a support for just themselves. Even using them on my C300 and 5D’s, which don’t have locking mounts, I’ve never had issues. The Zacuto system was discontinued, for the aforementioned reasons, they don’t need support.
Thanks for the suggestions guys. Didn't think about switching! You're definitely right.
It's for my work place, which is a rental house in an educational facility. The more support the better. Can't trust the students with 30k worth of lenses! Like to fully cover ourselves and them