<font color=blue>Von, the only trouble with lifting in the center is that when you remove one wheel, the tractor will tilt the other direction. Maybe not a problem if you're expecting it, but can sure be a problem if you ain't.</font color=blue>
Maybe that would be a problem with loaded tires but that's how I do it without loaded tires and there's no problem. Also if you just put the bucket down flat on the floor and it's not in float the tractor can't tip, even with loaded tires but if you wanted to be extra safe after jacking slide some blocking under the tire that's staying on. But for my money, as Von said, it's dead center and a very solid place to jack from with a floor jack.