It is all about the almighty dollar. I had these chains fall in my lap. They were used on police cars years ago and when it came time to get rid of them the dumpster was the choice.
Slow and steady wins the race! Sound to me like maybe you are asking a lot of the tractor. Spinning tires usually means you are trying to push to much all at once. I use very little weight on the back of my Case tractors about 200 pounds, I plow or blow with the storm. Usually I hit it after about 4" is on the ground, I'm also either pushing or blowing a driveway that's a little over 500' and another area that's about 4500 sq ft, rarely do I spin the tires, maybe a little at the end after a town truck fills the end with wet stuff.
P.S. Years ago I used to plow lots with big trucks and if we didn't plow with the storm, lots would take hours longer and also seams like there would be more equipment failures too by waiting until the end.
Unfortunately the snow gets moved when I get away from work and most of the time it is all done it seems.I plow snow on the streets and that holds me until storm is done usually. The 129 does push a lot of snow well. No complaints on the tractors ability. Just looking for more traction.