I've phased out 48" mowers a long time ago. Almost have my 52" mowers phased out. I can pretty much mow anything on my list with a 60" Turf Tracer, except a few gates. The only real reason I keep 52" mowers is because in some delicate spots, it is easier for my guys to not tear stuff up with them. Plus, I find that a 52" HP (s-series) throws thick/wet spring grass a little better than a full size 60" Turf Tracer. However cut quality is not as good with the 52" vs. 60" (especially thinner summer grass). Maybe it is because of the shorter blades, or maybe its because the deck isn't as good on the HP version.
If I could only go at it with two mowers, it would be a 36" of whatever make and a 60" Turf Tracer.