If you run anything smaller than a 40 with a 14 bolt you will drag it over everything. And you still will with 40's. Contrary to popular belief, the 78-79 D60 sucks in a TJ. Certainly there is more room to put a spring perch if you are running coils, but the pumpkin is so centered that you will run into issues with driveshaft clearance and the axle getting into radiator hoses. Your uptravel is more limited that with other front 60's. I have put the late 80's and early 90's Ford king pin 60's in TJ's and they work better. There is still plenty of room to put in a coil bucket. And unless you are breaking parts every time you go out, why get one tons? They are heavy. Your Jeep will be less streetable and your gas mileage will go down. They aren't cheap either. Teraflex, currie and dynatrac all offer bolt in 60's for a TJ and they are pricy, but unless you can do your own work setting up gears, lockers, and brackets, a set of junk yard one tons is not much cheaper.
That said. I'm part of the DD one ton club and I would never go back. My poor Dana 30 (RIP) couldn't handle what I threw at it. Do some research. Google Ultimate wrangler build up and swaps thread to keep you busy from now until your old.