half an inch over on each side, and an inch and a half front and back... seems just about perfect.
personal preference here... but my speakers are very similar as far as the overhang... when centered. However, I don't center them. I like a good amount of toe-in, and the smaller (upper) base allows me turn my speakers, without turning the stands , and still not see the base plate. After further searching, I see those RX2's have a larger footprint than my Hsus, but I still wouldn't worry. 21 lb speakers on top of 30 + lb stands (when filled... looks like 16 lbs empty each for the 22's) is pretty stable.