It will work fine. I have the same tractor only HST, and it drags everything around behind it like it's nothing. Yours will run that tiller like a champ. Have fun and be safe!
You shouldn't have any trouble. I just bought a 5 ft. tiller from Agri supply that is exactly like the King Kutter and I pull it fine with my Kubota L2800 HST 4wd. Your biggest problem is that you will run out of stuff to till very quickly! Have fun!