If you can do it, add the extra 2 rear (back) speakers.....use whatever you can get your hands on for now to try out and experiment..
I am using my old JBL L100 floor standers, and although they aren't a perfect match with the rest of my system, boy do they add that little extra something to the mix. I don't even own the 950 yet ( but very, very soon)....I'm using the Parasound CSE 6.1 expander right now for rear surrounds.... Worth having rear surrounds if you can do it. 2 rears are better than 1..........budoom!