While 8-40 screws certainly won't hurt, they aren't really necessary IMO when a reasonably light weight scope is mounted, <12oz. I've never had a problem with screws being sheared on any of my heavy kickers, 500S&W(700gr @ 1400fps, 350gr & 385gr @ 2100fps), 50kpsi 45-70 loads(300gr @2400fps), 499 Hubel Express and 50-140(570gr @2200fps), 460S&W (200gr @2900fps). All my scopes are mounted in low or medium rings, the higher the mounts used the more leverage the scope's weight has on the base at recoil. I also bed the scope rail in Loctite(FAQs) which really makes for a solid mounting.
Tim