I think either position will work. If you put them in the A position, you can compensate for the difference in distance to the listening area, and, consequently the volume, with your settings in your receiver.
Same goes for putting them in the B position. The woofers, though certainly close to it, aren't directly over you. Either way, calibrate with a ratshack SPL meter, and you should end up with a listenable situation. If at all possible, experiment with the speakers in something close to each position before permanently affixing them one place, or the other.
I think Ray3 has his QS8s on a shelf in each corner (sorta like A). Ray? Oh Ray? Get off the golf course, Ray, and in here where you belong! Sheeesh!
