I think it's mostly working now, there are a few minor hiccups but short of running Aruba networks equipment it'll do.
Here's what I did
- Mount APs in ceiling
- Set SSID, channel and encryption key to the same values
- Set static IPs for phones outside the DHCP scope
I also noticed that the D-Link APs weren't the fastest for renegotiating a link. The linksys APs running DD-WRT seemed to do better but the range went down even after increasing power.