Don't know the answer to that but I will say that that is the reason I went with a 48" deck. My yard is the same, uneven. Two inches isn't much of a difference. Maybe you need a 54" or even 48"?
Check with your local John Deer dealer. There are common parts among the Z500 series of zero turns, and should the rear brackets that hold the back of the deck be the same spacing apart, it is likely that a narrower deck from another Z500 series would fit with only a few additional parts and possibly a different belt. I am not sure of the deck sizes across the Deere lineup but I do believe that you would have to step down to a 54" deck to achieve your goal of navigating that uneven ground with more ease. 6-8" on a machine of this size and speed will result in negligible difference in the amount of time it takes you to cut. You would have to be cutting 1+ acres to add any substantial amount of time to your mowing and even then it might be 5-10 minutes.
I have a Z535 with a 48" deck, just for that reason, uneven yard. My buddy has the same mower with a 52" deck, so I would say, they are interchangeable.