When I auditioned an axiom epic 80/600 5.1 system The owner had the surrounds on stands and they were to the sides, facing in toward the couch.

The owner rotated the surrounds facing forward to mimic my future set up, and I could not really tell a difference.

FYI, My couch is against the back wall so my 5.1 surrounds are on the back wall facing forward, spread out about as far as they can be.

-David