Another take, based on personal experience.
My wife really likes the window seats, whereas I am not really fussed about them. We have found that taking (for example) 2F/2K gets one window, and pretty much just as easy to converse as in 2E/2K, but with the advantages that (a) my wife gets a window seat, and (b) the service is all on one side of the aircraft, so making buddy dining simpler - when in the middle the crews are a little flustered as to who is meant to be serving whom ...