i only grease the bottom of the slide, (under side of the beam) since the "keepers" are only 1-1/2" wide there isn't much contact area with the beam, so i just grease there to keep from wearing the ends of the flange/keepers...
nice setup for the lift mounts...
my mount bracket is a clevis type just out of A-36, the lift arms have bushings out of 4130 chromoly 3/8"wall DOM tube reamed to 1" ID, with a softer 1" 1018 pin also grooved for grease, with grease through the end of the pin. my pins are attached to the clevis bracket to keep from spinning in the bracket, so ideally only the pins should wear, then just make new ones when they get sloppy.