First confirm that the ft wheel is properly secured in the fork, sitting straight and tightly held. Only then move onto the brake. The initial attempt to center the caliper/pads is as you described. But i would spread the pads with a cone wrench (cleaned off) first to re establish the pad movement amount. After there will be additional tweaking of the caliper position WRT the rotor. I find that if I slightly loosen the two location bolts then loosen one fully I can "walk" the caliper over a small amount. Slightly tighten the looser bolt, loosen the other and repeat. This one bolt at a time method seems to allow smaller amounts of pad centering w/o misaligning everything. This is very much like adjusting chain tension on a single speed. By working one side of the axle at a time very fine amounts of change can be had w/o much frustration. Of course this assumes a rotor straight enough to not be the rubbing problem. Andy.