When I was first starting out, I didn't understand how the tail-wheel works. I adjusted the deck of my mower so it was flat with the ground, tightened up my top link and started mowing. I found that when going up over a hill, my tail wheel would come off of the ground, and when cutting down into a low spot, it wouldn't get down there all the way.
Then I learned off of TBN that you never tighten up your top link when mowing. You want it as slack as possible, but still able to lift the mower if you need to.
Now my shredder follows the contour of the ground with all the weight consistently on the tail wheel and three point arms. Even better is a finish mower with 4 wheels, one at each corner.