I'm planning on selling/trading my 2wd 3525 for probably a 4wd 3616. It will be used with a 5' bush hog, a 5' tiller, grain drill and a 8' tandem disc, plus the usual FEL work. I'm assuming the drawbar is strong enough for the disc. The 3616 is quite a bit lighter so should I get the rear tires filled?