Hi mchasal,
I've often praised how forgiving our QS surrounds are of asymmetrical placement--and they are, but such a radical difference in height may be problematic. But follow my guidelines and try it. You may be surprised. Plus the irregular shape of the room should auger well for fewer standing waves and better overall sound envelopment.
The different distances from the surrounds to the listening area aren't a problem because you can compensate for that in the setup menu of your receiver. My own surrounds are at quite different distances (and heights) and they work wonderfully (you must take care in the initial setup menu and use an SPL meter--get it at Rat Shack-- to carefully tweak levels).
Can't you mount the closer surround to the sloping ceiling on an angle nearer the height of the other?
Regards,
