I am looking to upgrade to Paradigm Monitor 5's as my main speakers over my mini's. currently I have 370cc, 2 mini's and 2 atoms in the rear. They are powered by a denon avr 1804, which is a 6.1 receiver. If I were to buy the 5's, I would move the mini's to the back, but what should I do about the rear center? place one atom there? can I put both? Is my only real option to upgrade to a 7.1 receiver? Anyone with adice, it is greatly appreciated.