Even with good enterprise grade Access Points like Cisco Aironet 1200's and with a managed environment (with WDS\WLSE etc infrastructure) you will struggle to sustain >10 active users per AP on 2.4Ghz. If you can use 5Ghz 802.11n\a then you may be able to hit 30 concurrent users and still get acceptable web browsing traffic. To set this sort of thing up properly you would need about 10 AP's with 2.4Ghz kit and you can not do that reliably without using a management system so you can be certain you are getting effective cell coverage and managing interference. Even if you do that the various 2.4Ghz client devices tend to misbehave a lot so if you cannot ensure a uniform set of clients you will struggle to get this to work consistently especially in an environment with a lot of warm wet human bodies moving around.
If you need to support 60 concurrent users in a reasonable space with 5Ghz WiFi standards things are a lot easier - there are (many) more non-overlapping channels available, the RF environment is much cleaner, the Client devices that support 5Ghz are generally much better behaved and you have that basic carrying capacity on each channel that is higher. You might be able to get away with just two but with 3 AP's it should work pretty well for 60 users provided none of them are doing unfriendly things like bit-torrenting or live-video streaming and you have an internet uplink that is fast enough - 100Mbps or so would be ideal.
