bush hog for Powermax

Weight of the hog and the capability of the 3 pt hitch to lift the cutter is an issue however. Rotary cutters of that size weigh from about 350-400 lbs on up to 1000 lbs for heavy duty models. Your little tractor may only have a lift capability of 500 lbs so the heavy weight units are out for you. Then there is the issue of the terrane. If it's hilly, you'l wnat a light mower for staility reasons. I have a 6 ft KingKutter that weighs about 725 lbs on my Ferguson TO-30. That's right below the lift capability of the three point(750-800 lbs). When I lift it, the front end is very light. It's OK on flat ground if I'm carefull but on hills, I need about 100 lbs of ballast on the front of the tractor. Soooo, I only use it on my Ford 4610.
My advice to you is that if you are hilly ground, get a 4ft cutter and pay attention to the weight, matching it to the capability of your 3 pt hitch with a bit of a margin. If you are flat ground you could go to the 5 ft but again be carefdul of the weight. I think you'll find, all things considered, the 4 ft will be the best for you. Just watch the weight. (IF you don't have live or independent PTO, get an overrunning clutch between the pto and the mower drive for safety reasons.)
Hope this helps you.