Boosting the 100-300 hz region will make the speakers sound "bigger" at the expense of some muddiness in the midrange. REW can find a minimal phase region in there to experiment with some tasteful boosting to find a happy medium. For the bass, my speakers were designed with an "EQ box" that added 5.2 dB at 32 hz with a Q value of 1. Despite experimenting with many customized EQ settings in my room, using boost and with sharp cuts at the room resonances (45 and 65) sounded best. As for averaging fixed mic positions, you can vary the amount of horizontal, vertical, and front/back distance to cover any area you like. I had a tough time obtaining repeatable MMM measurements- I think I was always pushing the mic too far forward.