+1 on the Sportsmatch adjustable mounts, 66's I think they are?
Anyways, best way to optically centre the scope isn't to count turret revolutions or clicks, that will get you in the park but for preciseness there are two methods, one quick the other laborious.
Quick route is to get a thick glass mirror, stick the scope on low mag and push the objective against the glass. Look through the eye-piece and move the parallax through it's range until you see two reticles. Simply rotate the windage/elevation until both reticles are on top of each other and you have a perfectly centred scope.
Then it's just a matter of using the scope mounts to sight the rifle in until you're within a couple of clicks of perfect.