set speakers large or small?

fronts 1.6 thiels 48hz-20khz,thiel center-47hz-23khz,rear thiel power points,75hz-20khz.reciever arcam 350,velodyne sub,should i set all speakers to large?
I concur with pretty much everything Queefee wrote, but add this cautionary caveat to his Pertinent Quotes: Just because AE was a brilliant physicist does not imply he was a brilliant philosopher. There are many things I'd rather know through reading, secondary observation, or generalization rather than direct experience.

Palen, the THX rationale is based on the contention that we are not well able to localize frequencies below 80 Hz, a contention I contend that is based on psychoacoustic evidence.

wow,a lot to take in,i did use a spl meter to set it up but my room is a little strange i think the best thing i can do is try differant settings and move my speakers around a bit,not much room for movement and cannot move sub at all.i would like to thank you all even though a lot of it was over my head
Set your front mains to large. Your center channel to large if you can, but try it in both to see what works best for your room. The LFE channel in movies is separate from the bass information that is routed to the individual speakers, so you aren't robbing from your sub by setting individual speakers to large. I have my Focal 826V mains set to large and the movie/concert watching experience is much more visceral that way.