Our scope mounts come drilled to an an industry standard 5 holes at .375" spacing. They are supplied with 5-40 screws. We recommend drilling your dustcover .175" below the top edge, and parallel with the dustcover. The scope mounts have an angle built in to account for the lockup of a 1911/2011 pistol.
Spacing:
Our scope mounts are designed to center over the bore on a classic .830" wide dustcover. This is the typical width of a short 2011 frame. Wide frames (Most LDC "long dustcover" frames, and our SDC frames) are .920" wide and require the "pad" of the mount to be trimmed by .045". To line up our mounts on an XWF frame, the entire pad must be trimmed off the mount to center the scope.