Pictures are very decieving when it comes to showing how steep a hill is. If he is having to lean forward on the 4 wheeler, its pretty steep. I would hate to spin out at the top and have to back all the way down. Will your tractor stick to the side of the hill without sliding if you spin out. An atv will go up a lot more steep hills than a tractor. When I was younger and dumber, I used to take my 4 wheeler up 60 ft highwalls in strip mines that were as steep as a horses face. Of couse you could get about a 30mph run at it and pull the clutch in 3/4 of the way up and coast to the top if you wanted. We also had spotters on the side of the hill to catch the 4 wheeler and get you turned around in case you didn't make it. I don't think spotters will be able to hold your tractor though.