Kubota M8540HDC, L5740HSTC, BX2200, BX2660, John Deere 425&1025R, Case, Massey Ferguson, Ford
I guess it comes down to what you're cutting, frequency and how much time and money you want to spend. For that tractor and acreage, I would probably go with an 8' twin spindle.
I'd feel better pulling a 12' batwing with that tractor than a 15' batwing unless it's never going to get into tall thick stuff. Or an 8' twin spindle as suggested above.