Glad to be of help, Scott. Your needs sound fairly basic and I think getting some mid-grade Ruckus AP's will give you excellent bang for the buck to start off with. It doesn't sound like you need a controller right away. As far as 2.4GHz vs 5GHz, there absolutely is a huge capacity difference. 2.4GHz in most public settings tends to be overly saturated by neighbors, close range bluetooth devices (e.g. wearables, headphones, fitness bands, and so on), as well as personal hotspots your bar patrons might bring. You will greatly benefit from 5GHz, as most modern smartphones and tablets do support 5GHz and use it.
You don't, however, need 802.11ac. So I think the 7372 is the right sized N solution for you, and the R500 is the right sized AC solution, and you'll likely need more than one to comfortably cover all your guests... though one would give you a pretty good start on your network already!
From what you described, it doesn't sound like AC is strictly necessary, though if you expect a few years' of lifetime from your solution, I would personally consider getting the R500 as a way of future proofing for a bit longer. I believe the 7372 was introduced ~2 years before the R500. Its predecessor, the 7363, is already EOL and no longer receiving firmware updates. Of course, an EOL AP is not necessarily a goner -- it probably will still work for some time, but it won't be able to keep up with the latest and greatest enhancements from Ruckus, and won't be able to participate in a controller based network with a newer controller.
So yeah, my recommendation is start with standalone R500 or 7372, and then maybe consider a controller if you need more insight / rate limiting if you find users abusing your service for heavy streaming or need to institute a captive portal ToS screen.