You'll need a set of these thinned bushings and shortened screws (4 of each) to install slim grips on your 1911. This set is stainless steel and includes allen wrench. Fits Gov't Model, Commander, Compacts and EMP.
HD-300-S-TS Slim Carry Groove grips for full size 1911 frames
HD-317 Slim Line screw and bushing set, blue