i have a 2320, 48 inch box blade and 60 inch landscape rake. the smaller box blade does require me to make more passes than if it was a 60 inch. however, it does bog the tractor down a bit when the box is full so i think a 60 inch might be too much for the 2320.
the 60 inch landscape rake is perfect.
you can usually find decent used box blades around if you aren't in a hurry and keep an eye on craigslist.