Honestly, I'd skip the Q2/RC2 plate.
I have a Manfrotto CF tripod, Manfrotto CF monopod, and had the 488RC2 and 234RC heads, respectively, that use the plate you're talking about. Obviously, I like their products. But I felt that the RC2 plate was the weak link in the chain. Support rating isn't the issue given your requirements - I used the RC2 with gripped bodies (5DII/7D) and big white zooms (100-400, 70-200/2.8 IS II), it held fine. The issue is that there's a little bit of play in the clamp. The connection is secure (and there's a supplemental lock), but that play makes critical adjustments a challenge sometimes.
I previously looked at the larger plates, but they all extend beyond the base of the camera and that isn't optimal.
Personally, I'd recommend getting an Arca-Swiss system. That's what I ended up switching to - I replaced the 488RC2 head with a Manfrotto 468MG (much nicer than the 488) and the 234RC head with a plain 234 tilt head for the monopod, and to both of them I attached Wimberley C-12 clamps. I use Wimberley P-20 plates on my lenses with tripod collars, and a Wimberley P-5 plate on the body. The other advantage is the available of excellent L-brackets (RRS, Kirk) for the AS system that are much better than the generic Manfrotto L-bracket.