This may help in your decision. I have a small fleet of tractors. Two of them have R-4's, and the others are R-1's and Turf's. If traction will be the main issue, go with R-1's, which will get more power to the ground. Also, with the rear wheels being adjustable; you can choose your own comfort level for the slopes. The R-4's are "all purpose" and do have their shortcomings. In muddy conditions, the tires turn into slicks providing little traction. But on a hard surface give a smooth ride, great for loader work, and with the wider width and heavier casings may add durability and longevity, working in unknown conditions, where a "flat" maybe a factor? They will provide a more puncture resistant tire? The down side for your tractor, the cost will add $400+ to the bottom line. I use the turf tires for lawn use only. If you are leaning to R-4's; you can also add chains for additional traction. The down side to my R-1's, are the front tires being narrower, tend to look "stressed out" with a max. loaded loader bucket with max. tire inflation!