Yes, the seating definitely has to be against the wall - my viewing line already has to be across the narrower distance (12ft). But I thought the ideal position for 4 Atmos were all forward of the seating anyway? Also that the 4 Atmos were each on their own channel, so would be adjusted individually for balance? But hey, if I'm not going to be able to tell 2 from 4 Atmos speakers in that room (at least not noticeably ) I'm all good with that!
And once again, I'm not going to be able to listen to different setups in advance, so I'll just take (what seems like) the most logical / sound advice I can find, and run with it