@kaijin 

Hi,

in general i say connect to the non overlapping channels (even if there are other accesspoints). The devices also the other accesspoints hear each other and react on the same channel to produce the maximum throughput.

Chosse the non overlapping channel with the most far away devices. You see it at the signal strength of the devices.

But you can test to find the "best" channel and choose what ever you want. But you will disturb the others and the "loudest" wins .

Best Regards.