I used to have one (bigger wheels and 2 big 'wheel's on it to raise and lower the blade). Always thought I should remove the front wheels (it was horse drawn once too) and fix the front to the tractor drawbar. Never did, but it can do a good job of levelling. The comment it is light in the shorts is right on, and adding a person wouldn't change that enough. If the wheels can take it, add 500 - 1000 pounds along with your hyd. rams for tilt at least, angle if it works out, and then rely on the drawbar being a 3pt drawbar to control depth of cut.
My wife still remembers when I would drive and try to give her instructions on the big wheels, or she would drive and I would try to give her instructions where to drive. Neither worked at all! /forums/images/graemlins/frown.gif That was probably the biggest reason to sell it. Now, with the hyd. possibilities, wish I had it back (at least I did before laying down asphalt on the drive two months ago /forums/images/graemlins/grin.gif )