Yup. We aim to confuse.
Not sure what your tractor is rated for hp, I sure can't see 50 hp running a 12 foot hog???? Possibly an 8 foot, more likely a 7 foot? The highway crews run 15 foot models, and use 150hp or bigger tractors.
I run a 12 foot flail mower with 60 hp, and would not want any less hp - I can bog it down, but it runs fast enough to need to hang on to the trctor. But I think a good flail might do more of what you want than a hog. Flail doesn't like rocks and stumps very well, your rough ground is just rough, not obstructions?
Now, for my soapbox, which you can please totally disregard.
Why would someone want to mow 50 acres just ot mow it? Put that land to some use - rent it for hay making, or crops or something. Go native and let prairie grow on it. Pasture it with critters. Sure seems wasteful to me to mow 50 acres for no gain. I farm for a living, I have a 8 acre wet area that I still float a small tractor and hay mower over it, make hay off of it even if it's not the best hay, just can't stand to waste land, it's all so valuable for growing feed/food. Can't imagine just mowing 50 acres for nothing.
There, I feel better. Off my soapbox. You might have fire issues and need to keep it down, or it's just yours, you can do whatever you want with it, none of my business.
Without knowing the situation, I think perhaps you need to look at 50 acres of wild territiory a little differently than you look at a golf course, and let it be a little tangled and uneven. The flail mower might work a tad closer to what you want, but I don't think you can actually do exactly what you want - rough ground and smooth lawn just doesn't add up.
--->Paul