Michael, welcome. The info in your second post clarifies things significantly and indicates that you already have the speakers to try out various center channel possibilities. I experimented in the past with one center, two center and no center(speaker)arrangements. A discrete center has the advantages Alan mentioned in anchoring dialog to the center of the screen and allowing the center channel volume to be increased independently of the mains to help when the dialog has been mixed relatively low. Note that the dialog(with a "phantom" center)doesn't suddenly switch to the nearer speaker if you move off center; it stays in front of you as you move and will go out as far as the speaker on that side.
Using what you already have, first try the M22s alone to see if the "phantom" center is satisfactory; don't assume that it isn't. Then use your VP100s vertically directly at the sides of the TV to see if that discrete center(which still would have some image shift with movement to the sides)would work well for you. Also, simply put one VP100 vertically on a temporary support under the TV in front of the cabinet(or even try both there vertically positioned directly alongside each other). No good reason to be thinking of spending more money yet.
