I made custom shims. It takes a bit of trial and error to get it just right. Your wanting to accomplish two things. First, make the round male cup part snug in both cups so there is no left to right movement of tailgate. The second is to determine thickness of each side to make the same gaps. I used a 1/8” x 1” bar stock on drivers side that required just a bit of grinding down. Maybe ground down a 1/32. The passenger side took a thin shim about 16 gauge. This combination moved the tailgate left to right for perfect gap and snugged both cups into sockets with no slip left to right. Hope this makes sense.