I think what Near Miss was getting at is that each rifle will perfom better at different torque values. In my experience with aluminum pillars, I would say to start at 15 inch pounds and work your way to 40. Shoot several groups at each new torque value. I've also found that the first group is usually an anomoly, disregard it good or bad. The action kind of settles in under it's new torque value each time you tighten or lighten it.
Did you put your 457 together yourself? I love my T4 stocked 455 VPT! My 457 VPT has a version of the PRS1 Manners stock. Either way, they are incredible stocks!
Disclaimer: 40 inch pounds is not recommended for the polymer pillars in all other CZ 457 models. I never torque beyond 30 inch pounds with polymer pillars.