I pull a swisher 60" finish mower offset to the side behind my tractor to do all my mowing. I don't have any slopes as steep as yours, but out of the box I'd say it tilts about 30degrees. If you need it to tilt more you could modify the hitch it comes with. You could build something for your 3pt to extend an arm another 5 feet which would allow you to reach 10 feet into the slope. It cost me $1300 new. A specialty tool would be a lot of money and can't be used for much else. At least this you could use to speed up some of your other mowing chores.