Mains are Mezzo 6. Center is Mezzo 5. Surround channels will stay as is. I cannot move my wall mounted side surrounds position lower on wall unfortunately.
As shown here but in black oak:

http://www.soundandvision.com/content/mordaunt-short-mezzo-6-speaker-system#8AUYDGZgELjQrodB.97

Ceiling height is 7'6" with backer boxes roughed in with wire in these locations. Accurate (but old) layout diagram.