most are just hangers and not load bearing. if the clamps not got enough surface grip leaning on the door could make it slip, no?
IDK i'm just tossin ideas..........for all i know those could be some sort of insert in there now.
actually it looks like a smaller punch with a big base die allowing some push down and coning b4 it breaks the bottom out.........i might could do that at work.
The clamping force is solely generated by the amount of torque on the screws, so the force is the same whether contact is across the entire plate or isolated to the nutsert face. What ends up holding the mirror in place is then friction created by that clamping force, and friction is mostly independent of contact area. I say mostly because when the contact area becomes very, very small, the frictional force can actually increase a bit because embedment can occur (one piece digs into the other because the contact stress exceeds the material strength.)