I'm sure Johnk will jump in here soon as he is the big classical fan amongst all of us.
I don't believe you need floor-standers for your room size. You may want M22s (or maybe M3s if you want the sound to be more laid back). And the centre is certainly not a necessity. When I listen to music in PLII or Neo, I usually disable the centre for a more spacious centre image.
If you listen to bass or pipe organ, with the money you save on the centre and fronts, you should consider buying a DSP-based sub. The EP400 would be a good one for you given your room size.
Good luck with your purchase.
