A L bracket/plate may or may not help with a heavy lens, this depends on the specific lens.
Ideally, the camera+lens should be supported under the center of gravity or close to it.
Unfortunately some of these lenses do not have a tripod mount, so you are back to supporting on the camera.
Like others, I converted to the Arca Swiss mounting system, and I like it.
The hassle is, especially for a business, you have to convert ALL the tripod heads, ALL your cameras, ALL your lenses with tripod sockets, and all your flash brackets. You need to convert everything, so it becomes a standard. Because you do not want to be in a situation where you have a AS clamp on the tripod and no AS bracket/plate on the camera or lens. The more gear you have the greater the number of items that needs an AS clamp, bracket, or plate.