I think width is key when mowing 14 acres. I still think that to go wide you need to go away from a rotary cutter - a flail perhaps, or I guess a batwing which is a sort of rotary cutter. I'm a big fan of going slower and wider, which often means running a bigger cutter than the maker recommends - they have to spec it as if you're going to run full speed, if you're not then a) your back will thank you, and b) you can run a wider cutter.