I have read many articles about small vs. large settings. Try them
both, however, in my opinion if you have floor standing speaker set
the receiver to large, if you have a decent size center set it
to large and surrounds to large if you have decent size surrounds.
What I mean about decent size center and surrounds if the speakers
can go down to 60 hz. I set the cross over on the sub or reciever
to 10 hz above the main speaker lower frequency. Then adjust your
gain (volume) on the receiver sub output up and do your tone test
to balance your speaker.