Just my 2 cents but I would rent a stump grinder. BTDT. They take a wicked beating and one attached to your PTO is going to beat your tractor. Back in the day when I lived in CT my neighbor and I rented a Rayco Super Jr RG1625 over the weekend, ( they only charged for 1 day on weekends) we ran the crap out of it and were on the last stump when we hit a huge spike, broke a high dollar Kevlar belt on it, Oh well not our problem. If you only need it once in a while rent it. Unless you just gotta have one. Link to the company we rented from.
http://www.superiorrental.com/rental...arge-w-Trailer
Oh I forgot it will also grind rock outcroppings so you don't hit them with your mower blades.