Gravely ZT HD 48" or 52"

After checking out several models I've decided to go with the Gravely HD series instead of the Hustler Raptor SD. My only hang up is deciding between the 52" or 48". It takes me about 21/2 hrs to mow with a conventional 46" rider. I have a fairly steep mound system that I mow and about 10 - 12 trees,shrubs,etc. Since there is only $100 difference in price I was thinking the 52" but not sure if it will cut as good as a 48". Any sugestions from those of you that own either one would be appreciated.