Unfortunately, the rails on the frame so that they must be fixed and not queer along. Say you can see the camera left / right slide in the holder.
Depending on the application this may not be a problem, or you do it already so I had it but always different, so you can move the camera forward / backward. With larger lenses, the holders are also designed it so. Uu one must therefore from time to time the plate on the tripod to turn 90 degrees which can be a bit annoying.
Unfortunately, all alternative products appear to be identical, that one could attach to the frame here at most again turned more mounting plates to 90degrees - The appropriate locations / threads are present, the whole, however, will be quite bulky.