And some days, not so much. Finally got a chance to finish up the job, and the two 'new' tires just popped onto the newly-painted wheels quite easily. A little bit of practice, the right hand tools, and decent components makes quite a difference. Took about an hour, including mounting the things on the trailer and cleanup.
No trouble seating the beads, they just popped into place. I didn't really have to do anything more than apply air to the stems. I'm sure that varying rim widths, etc, could affect that. Soapy water sprayed on the beads showed no leaking, we'll see how they hold air over time. The trailer's spare is now mounted vertically, being held against the front rail by the tongue-mounted hand winch, its hook looped through a lug hole. Lying on its side on the deck out in the weather is what had ruined the old one to the point where it would no longer hold air, yet wouldn't come off the rim either. Vertically, the water will drain out of the bead areas. -- Jim