I just use my ears to guide me. That's quite unusual for me because I am very data-driven. I have found that Audyssey XT32 works better for me if I calibrate very close to my ears. I only use three measurements: MLP, 6" to the left and 6" to the right. Belive it or not, this also sounds better for all my other seating positions around the room.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated