I owned a side-clamp style Chameleon, but looking at a couple pics and the diagram to the back-clamp design, it looks like these are a "set and forget" thing? Unless you have a collection of warped frames...
You should make sure the clamp/screen is level to the pallet, tighten these down and forget about them. (right?) They have a nylon lock nut, so once cinched down tight they shouldn't back out.
It's not like these are used for off contact adjustments like an old Hopkins machine, the off contact is mechanically separate.