The one thing I would suggest is to hard limit your 2.4G channels to 20Mhz instead of 'Auto' unless you like to be the source of your own problems. There are only 3 non-overlapping channels in NA and a surprising amount has been written on how to optimize them. Let me just give you one example...let's say you do a standard 1,6,11 deployment...but your AP on CH1 switches to 40Mhz BW to service users...well, it is now stomping all over your CH6 APs and users...and everybody has a bad time. 20Mhz is good to 80-90Mbps even with just 802.11ac tech, and if you need more, the idea is to add more APs and dial back everyone's power so you can crowd your 1,6,11 cells closer together. This is becoming every more important in congested areas where everybody is stomping all over each other...I was horrified to discover that internet modems from the big providers here are spewing RF on many channels, even when not being used. The 'Fibe' product around here has 2 x 2.4G radios, 2 x 5.8G radios and a Zigbee radio. You can turn off 2 of the 5 radios, but the others are hidden, full power, on whatever channel they find convenient (even if you don't subscribe to the TV package...shame I say!)
and an example of good frequency planning for APs (2.4 on the left, 5.8 channels on the right)
My threshold is -80dB for foreign signals at my point of use. Meaning...if my neighbour's Fibe box is blasting my office at -70dB...I'd better pick a different channel if my AP is across the house and also in the -70dB range in the office...that's just a lose-lose situation.