Might be too late for you, but I recently asked what dining rotations there were available and in my request I picked the one I wanted (5-nights on Magic, May 4). I thought that was easier than saying Rapunzel's x 2 and Lumiere's x 2.
FWIW, I was told by shoreside Concierge that Concierge guests are ALWAYS seated at private tables, but it definitely doesn't hurt to ask! We went on our first cruise and were able to travel concierge and I was BLOWN away by how accommodating they were to any of our requests! I ended up leaving the cruise thinking that we could have asked for a LOT more, lol! Enjoy your cruise