I've found that usually a maximum of 20% of users are actually on a WLAN at any given time. So I would consider 2000 users for calculations. If then you take that each AP can take at least 250 users and you have 60 APs it means you've got a 15000 user budget there.
Just don't forget to disable non OFDM and raise BSS minimum rate IF applicable. Depends on the environment, but you could go to up to 24Mbps minimum bss rate.
And if APs are condensed in one location, like a stadium, use directional antennas.