I have used the side of my bucket many times to break a tire bead, small mower tires up to large truck tires, I have found that rotating the tire between several presses using the bucket, basically loosening the the bead rather than just ripping it off (don't use a cutting edge or tooth bar), you can also press the tire with the loader bucket and hold it, then hit the tire with a large hammer.
As for inserting the tube, it would be alot easier if both beads were broken and you pry off one side only, so you can lift the tire up, place blocks of wood or bricks to hold it up, while the rim is flat on the ground, position the tube evenly around the tire, then pry the tire back on the rim and inflate.
tractor tires can be heavy and stiff, laying the tire out in the sun for a few hours will soften them up a bit too. For those who use either or starting fluid, I take the valve stem core out before setting the bead, this way some of the pressure can escape after the bead is set. ( a little less dangerous). Be careful, fingers don't grow back. and always chain the rim to something it can jump 10 feet when the bead sets. before using either I always try air from a pig ( small tank with a large valve ) while a clip on air line constantly blows in the valve stem. for small tires a clip on air line blowing while I bounce the tire in the vertical position has worked many times for small garden style tires. I only use either as a last resort, I have seen a tire explode, not pretty, the bead had been ripped and the tire blew off the rim while setting the bead, lucky the rim was held down to the tire changing machine.
Just some advice from a former tire changer.
MrC.