Catvet, I was having some problems with tire flats due to mowing hawthorn. What i did was create a set of tracks with channel iron. I used 8 in by 16 in the rears and 6 in by 12 in the front. By lying the pieces on the floor with the "C" facing down and welding 3 links of chain, one to each channel and one in the middle to piviot, I made them about 6 in shy of the circumference of the tire. by driving up on them by tying a rope to the end one and having it curl on the tire as I drove onto them, I just deflate the tire, bolt the ends together, having two holes in both ends, and reinflating the tire. I did weld on 6 pieces, inside and out, that were 3/8x31/2x6 to keep the sides centered. I can tell you from this setup, I didn't get anymore flats, and I was able to go where ever I pointed the frontend. The difference in floatation was greatly improved, as was the traction. And I might have had 200 bucks in the whole system with the exception of an afternoon of welding.
I did this for a 5300 50hp JD. I am sure it could be scaled to work for any tractor out there. It also adds a few inches of ground clearance.