I've got a set of poly bushings that came in the Clayton's (Rock Krawler) leafs that I toasted in just over a year of wheeling, they pressed right in with c-clamp pressure into the YJ/XJ bastard pack I replaced my toasted springs with. The old ones in the pack were the standard metal sleeved factory ones, they took a bit of PB Blaster and a hammer/big socket to drive out of the spring eyes. That metal sleeve just seems like rust/stuck bushing waiting to happen.
I've never heard of different diameter bushings for XJ leaf eyes, that's weird. The overall width is slightly different depending on whether the bushings are shouldered or not, but there's plenty of room in the stock spring hanger and shackles can be slightly bent open/closed to account for this.