Magnepan and room size, room placement

I have always been a fan of Maggies, but never an owner.  I am thinking about them again.  One of my issues has always been room size, specifically as it relates to the rule/recommendation that the speakers be placed 3 feet from the front wall.  I get the scientific argument about dipoles and the rear sound radiation.

first, let me clarify that I am thinking about the 1.7i or the 0.7, not the big ones.  Probably the 0.7. 

my room is about 10x10.  With a listening sofa of about 30 inches deep along the back wall, if I put the speakers 3 feet from the front wall, the speaker to listener distance is less than 5 feet.  Even less if the 3 feet is a minimum. My current speakers (Proac monitors on stands) sit about 20 inches from the front wall.  This location was arrived at through much trial an error, and really is a sweet spot.  Having said that, I am willing and able to spend some time playing around with position of the Maggies to find their sweet spot.

but my question really is, just how important is the 3 foot rule/recommendation? Does much of the sound waves really get cancelled out?  Does anyone have experience with Magnepan closer the the wall (18-24 inches) ? What aspect of the sound do you know from experience (or would suspect) would be most compromised by being too close to the front wall?

While the obvious answer is a home demo, talking on the phone to my two local dealers (in Chicago burbs and Madison, Wisconsin) indicate that a home demo is not possible to to their concerns of transportation damage to the large speakers, as I live 1-1/2 hour drive from either.  

thanks for your help,

Bill