My only concern is that when tightening the screw clamp onto my shelving unit, it just never felt like it had a solid grip

weak grip, but it sort of works.

There is no way to get a truly secure grip on your desk

The clamp mechanics allow for a very wide range of desk surface thicknesses, while still maintaining a secure, non-slip grip on the desk edge.

and you end up overturning the plastic knob, bending the plastic but never quite getting a solid grip