My thinking, really, is this...

When I watch movies, I like to have a sub/satellite type set-up where all speakers are set to small. This, in theory, allows the mains to operate more efficiently, as they no longer have to worry about bass production.

When I listen to music, I prefer to have it be in 2 - channel mode, without the use of a sub... just personal preference. Thus, I was hoping that the large/small settings could be adjusted per input. It appears this is not the case, but I appreciate all the feedback.