Vivid

I will be receiving a brand new pair of Klipsch RS-3 II surround speakers this Tuesday to replace some older Paradigm Monitors I was using, my first question is because of a rather large window on one of the side walls its impossible to have both side speakers @ the same height unless I mount them directly under the ceiling which makes the top of the speakers 8-0 high. 1. Is this too high & will there be any negative effects being so close to the ceiling? 2. If I mount 1 speaker lower then the other say 12 would that affect the surround effect? 3. Should the side surrounds in a 6.1 system be mounted @ the same elevation height wise as the rear speakers, I will have about 12 difference here. 4. Ive heard people talking about angle mounting the side speakers down towards the listener, is this a special wall mount available for the RS-3 II or just use a Omnimount kit?