In case of this 3 different access point models i would recommend you a channel sheme using channel bounding of two channel (40 mhz channel width). In high density deployments only 20 mhz could be a better decision, if you use smaller cell sizes to fit for more clients. The newest ap model 3825 support 80 mhz channels, but this only will work well, if you designed your wireless network to fit for this.
