I agree with Robert, the first thing I would suggest in a hotel type environment where you have limited control over the devices introduced, is to disable Channelfly, allow background scanning to manage the channels, only use channels 1,6,11, probably set the background scan time out to 2 minutes or so - it'll probably default to 20 sec which will cause a lot of channel changes in a hotel due to the introduced interference.
If you can get remote access to the controller CLI, set the WLANs to OFDM only.
Considering you are running R600 etc, you should be able to check the 802.11r and 802.11k which will probably help movement and allow you to potentially get better client information from the controller if their device is 802.11k compliant.
I have no idea how the site was deployed and what your surveys look like, but if your 2.4 is covering everything so well with that much overlap, you may be able to drop it down by just 2 or 3dB and test again for coverage - you may find the coverage is still good and there is less overlap on the 2.4, giving you cleaner air and probably higher throughput.