I'd also suggest lots of experimentation - and don't rule out the possibility of setting any speaker whose bass holds up down into the low 30's to LARGE. Back in the days of stereo and no subs (gosh that was long ago!) that's how I ran my current mains - and that's how they are running in a multi-channel, multi-sub environment today - because that's how, to my ears, it sounds best. There's no harm in playing around with it.

Jeff Mackwood