Hi Leningrad. I live in northern Vt. I have a 1/4 mile gravel drive, and it isn't flat by a long shot. I plow my driveway with a Woods 84" rear blade.
My tractor is A 26 hp Cub Cadet 7260. All tires are loaded R4's, and I run chains on my front tires. When I bought my tractor, the dealer included an 84" rear blade, a no-name blade of dubious quality. I broke it 3 times the first winter I used it. After welding it back together the 3rd time, I went and bought the Woods blade, and I never had to do a thing to it over the last 20 years. So, using my experience, I would recommend guying the best, heaviest duty blade you can afford. Plowing snow, on a gravel drive, is very tough on both the blade and the tractor. At least a couple of times every winter it seems my blade will seek out that one frozen rock just barely sticking out of the driveway and it will stop me dead, or will try to spin the tractor around. That's what broke my old blade. The Woods bade just takes it in stride. It also has a curved blade, not a flat blade with the top bent over (like my original one was). Another person mentioned this, and it really does make a difference when plowing. The snow rolls off the blade much better.
My bade also has the ability to shift from side to side. VERY handy, especially in the spring of the year when you need to push your banks back to make room for that last big spring time snow fall. It allows your tractor to stay in the driveway (where you have the most traction) while you push your banks back. This is also where the chains on the front wheels really shine. Without the chains on the fronts, having the blade angled off to the side will constantly try to push the front of the tractor around. A couple of folks have mentioned that they plow with the blade backwards while the driveway is soft, and the normal way when it is frozen. This is really good advice.
Another handy feature of my blade is it has the ability to go almost vertical. This works well when you need to clean out your ditches in the spring. I straddle my ditches with the tractor, and go the length of my driveway. Works slick as heck.
Hope this helps a bit. One Vermonter to another!
Corm