Well, I actually thought that if I used those expensive slotted washers you sell for the purpose of removing the slop from that slot would be a good start. And also knowing why the slots exist and that it was designed to allow some adjustment that could be then locked in position with a cam washer helps too. And from the pic it seems like the bolt has been worn down makes me think it has been moving despite it being tight explains my response to get a rod end that has the same size hole as the bolt's diameter.
And as my TJ does not fly why do so many linkages seem to fit the mounting bolt? All those engine crankshaft bearings seem to fit the bolts pretty snugly. Actually, the only time I remember using a 1/2" bolt in a 1" hole is when I was half-assing something.