"I've had 4prs of Maggies, to me 30" is minimum in most rooms." As a general rule, I agree. I have found that placing some of these on the wall behind the Maggies, allows a closer proximity: (http://www.ebay.com/itm/CityBlox-Acoustic-Foam-24-sq-ft-Next-Acoustics-Studio-Soundproofing-/281719194106?pt=LH_DefaultDomain_0&hash=item4197c5c1fa) or (http://www.ebay.com/itm/2-x-12-x-12-inch-Acoustic-Pyramid-Studio-soundproof-Foam-Tile-shipping-discount-/351420139506?pt=LH_DefaultDomain_0&hash=item51d245c7f2) I have mine placed only in the area that the panels will most directly radiate(based on their toe-in).
