Kingpin bushings are finished in place, so they require a sizing reamer, as well as a stepped bushing installer.
The first task is getting the old kingpins out, which generally requires a specialized vocabulary and an acetylene torch setup. I've seen a SawzAll involved on some as well. Once you get the kingpin out you have to get the old bushings out, that's where the bushing installer comes into play. Or a hacksaw blade. Then clean the bores, push in the new bushings, ream to size and to make parallel (ream a little, try dropping the kingpin through the bores, ream some more . . . ). After that, it's simple to reassemble, but it's usually a big hammers and lot of heat job. At least is has been for me.
But loose kingpins will not give you lots of slop in the steering wheel just sitting in your driveway, so ascertain what's up with that first. You'd checked the rag joint, now look under the front end at the steering box's Pittman arm while someone else gently rocks the wheel back and forth through the play area. My off-the-top guess is that you have a damaged steering box. In general, I've found that you can adjust out very little play via the adjust screw. Anything more than one turn, and you'll find it binding on turns (not good!). The sector shaft bushing goes bad on the Ford boxes very commonly -- that's the shaft that comes out of the box to which the Pittman arm is attached, and instead of turning, the shaft moves around in its bore. That's where I've seen the most play in the box, but the sector gear gets worn too.