My HC is a loft conversion - the side walls are vertical for 3ft, then pitch at a 45 degree angle with a flat "roof" . My question is this - I currently have a 5.1 speaker system (Quadral Ascent line)fed by a pioneer 908 receiver, But I fancy upgrading to a 6.1 system (via the new Denon 3802 receiver). the rears are currently on very deep shelves about 4 ft behind the seating position (bipolars) - should I get a new pair of bipolars and mount them on the 45degree angled walls either side of the listening position , and use my existing rears for the EX/ES channel ?? Is it more important to match the sides and fronts,or rears and fronts ? (Quadral dont make a "flat backed" speaker, so couldn`t match the wall speakers to the rears). Any thoughts appreciated,as always.