Wlan - subnet size

Question

I'm wondering if there's a best practice regarding the subnet size of the dynamic interface.
Is for example a /16 recommended, knowing broadcast/multicast to the clients are disabled.
I've a setup where via aaa override, the users are placed in their corresponding vlan: admin (wlan I), staff
(wlan II), guest (wlan III). There's only a wlc on the central site. So all wireless traffic from all sites (connected via fiber) are passing through the wlc. 
I'm wondering if there's a difference (performance,other?,...) between a solution with three vlans (one for each ssid but large enough) versus
1)ap group solution with dedicates vlan
2)assign a vlan via aaa override based on 'location' and function (admin,...)
(staf from site 1 = staf from site 2)
So what are you thinking?
Pro's /contra's of a big subnet in this situation and in general deployment

Answer 1

Davy,
I chuckle when people ask this question. I say this because we are all use to small subnets, because of the broadcast / multicast drama that happens on the wired side. As you pointed out, the WLC proxys this for the clients so its never sent over the wireless.
Ive designed many a WLANs. I normally lead with /21 or  /22 which in most environments works well.
If there are specific location needs, perhaps NATing or special security segmentation one could venture to use AP groups. This would allow then piece of mind knowing each location is defined by an AP group. Good example would be something like PCI. This could also aid in management as well.
So if you find yourself needing more control in the future, ap groups will give that ability.