My Cornwalls have never created a wider higher deeper soundstage than when I followed the Golden Triangle formula as described here: http://www.cardas.com/insights/index.html
When situated ideally, the fronts of my Cornwalls are 5 feet away from the back wall. Unfortunately, my listening room is not large enough to accomodate situating my speakers that far from the walls while still keeping my wife happy so they generally have to sit in a less ideal position.
Regardless of how the soundstage was achieved in the studio, proper placement of the speakers will take advantage of all the imaging the sound engineer was able to create with his mix.