Update. I got a chance to move the right speaker to the center and audition it there, so here are my opinions. The RC-64 III is an excellent speaker. Timbre-wise, there's no question it matches. Its also dynamic due to its efficiency. No more amplifier compression during loud noises. Unfortunately due to the acoustics in my room and the way the ceiling was made, its easy to pinpoint the center. Like, you have this big wide sound stage with the left and right, but then this small center point, which is saying something due to the center's size. You can hear it even if you're off-axis, but it feels small in comparison. My ceiling is made like a set of stairs. The highest part of the ceiling is where my couch is. Then there is a step down where the equipment is, and I fear that due to this step down, the center sounds like its boxed in due to it being horizontal. Before I got this center, I used the Monitor AUdio RSLCR vertically. Though the speakers weren't timbre-matched, I was satisfied by using it vertically. It sounded more seemless that way as opposed to using it horizontally.
SO, I moved the right speaker to the center and listened. Lets just say, I can't unhear what I heard. The first movie I tested it with was Fellowship of The Ring. There was plenty of content to fill out the center. Though the RC-64 is closely matched to the RF-7 IIIs, using a RF-7 III for a center takes it up a notch. And the focus, O the focus. I knew when something was in the center, and it sounded just as full and huge as the other 2 speakers. I'll probably have to turn the center down a db or 2 to get a seemless blend with the fronts. I'm quite aware that not all center channel soundtracks are created equal. Many older movies won't have as much detail due to using production sound versus music and other sound effects for the lefts and rights ... today there's not as much of a distinction. But I was convinced. Third RF-7 it is. I already rearranged my shelving to accomodate it, now just have to make the exchange.