What combination of parts do you have there?
On 911 struts, the brake stone guard bolts directly to the spindle with (3) 8mm hex head cap screws.
There is no spacer between a 911 caliper and a 911 strut.
The rotor should be centered up in the caliper if all the correct parts were used. Are those 911 Carrera rotors with 911 SC calipers? That combination probably wont work as the Carrera rotors were thicker than the 911SC parts and the 911 Carrera calipers were spaced wider than the 911SC to account for the additional rotor thickness.
I have not run into this problem.
One other thing I see in your picture, but it may just be a funny angle, your bearing grease cap looks strange. Not quite the right shape. Are you sure that they are the right parts for the hubs?
Just my $0.02
Click to view attachment