I like big tires as well. (I have 15.5's on mine with 14" rims.) I don't know what tires you have now but a good set of 13.6x38's with 80% fluid will pull unbelievably. We have always kept Dad's '51 DC(bought new) in good 13.6s and for it's size it is the best pulling tractor on the farm. A 10' disk is PLENTY for a DC, especially in spring plowing.
Glenn F.