strube, it looks like you guys have at least a few, if not several, more inches of space between the center speaker and pic? I would do my best in getting if off the floor as much as possible, and since you guys have no issues with using velvet on top of the speaker, I am not worried about reflections whatsoever.
Getting away from the masking midbass boosts is a worthy goal, besides the other benefits as well.
If you guys ever need to increase the angle of the center, I used to have two of these (biggest I could find at the time). Whoa, looks like they went up in price, hmm, maybe find them elsewhere, oops:
http://www.amazon.com/gp/product/B00006IATN/ref=wms_ohs_product