I made a metal bar that hooks on the Rumbux cross bar and props the bike back so the rear wheel is on the ground, (just), and the front is off the ground. It fits in the sadddle bag. It was just a piece of light tin channel I had from the crossbar of a Uhaul box for hanging clothes.
You could find a piece of wood like a 2x2 and cut a notch or Vee into it so it can be used against your skid plate or the header pipes as a prop. It's not taking a lot of weight when the bike is on the center stand.
This can be used to remove both wheels as well, with some caution. Rear first, then front. I'll be doing this on Friday in PA to get tires changed away from home.
Alternately, improvise with what you can find laying around to prop up the bike. Worst case, just put the bike on it's side. People have been doing that forever for road side tire repairs.