Chris, the idea is to have the speakers maybe an inch in front of the stand surface to minimize reflections and refractions. With the current Energy center, bring it forward and stand it up vertically.
The suggestion to try the M80s to form a "phantom" center is a good one. This is done simply by setting the center speaker "None" in the 888's speaker setup menu. Any center channel material is then automatically sent equally to the two mains which create the image midway between them. The advantages of a separate center speaker include keeping the image in the center for listeners off-center(the "phantom" shifts with the listener)and the ability to set it louder independent of the mains to compensate for dialog set too low in a movie.
For a better center speaker, the VP160 or VP180 would be fine, but a more economical choice that would do the job is a vertical M22 that essentially matches the M80 above the bass area. Your stand appears to be about 20" high, which would be ideal to make the M22 also match the M80 height. You could experiment with one of your present M22s, or even use both of them side-by-side.
If you have other Energy speakers, they could be used as surrounds. Using those speakers at close range as surrounds in your small room might justify experimenting with placing them to the side of the listening position, but facing toward the back wall to get a more diffuse sound suitable for surround effects.
