I have always gone by "feel" using the supplied allen/torx, or a B-Square driver kit. Once I did use a craftsman torque wrench to mount a M1a scope mount, as the directions for the mounting bolt were pretty specific. That said, a good torque wrench is a good idea, as a lot of folks tend to use to much torque, stripping and damaging screws, especially with aluminum mounts. I have used a drop of Lock Tite Blue on mounting screws for years, and never had one come loose from recoil.
Larry