Good luck. The sound should be essentially identical between models, with the exception of bass extension, which is better with larger panels. Smaller rooms also have better bass extension. I had the Quad 2905 in my main living room (picture above) and when i moved them to the office directly below, same footprint though with 8′ celing and not open to other rooms, the bass was enhanced quite a bit.
My panels were wrapped in plastic when i received them, it does make sense to protect again rain, but i didn’t really think about it.