I think masyado ko nga ata nahigpitan, kasi may tiny, shallow scratches na yung pads na kita sa pics below. How tight is tight enough nga ba?
That's pretty normal, depende rin sa material nung pressure pads. Mayroon kasi made out of zinc, hardened steel, etc.. which have varying degrees of hardness.
Personally, sa akin, pag hindi ko na maikot yung lock nut screw with the allen wrench, that should be tight enough.