Thanks for the information Sean.

The Manfrotto ball head I'm using is nice, but the RC2 system seems unstable and I think is causing some sag right after tightening the ball head. I've wanted to get into the Arca Swiss clamping system so I picked up a used 6D plate off Lens Authority and a new Wimberley C-12 clamp that I intend to use to replace the RC2 on my 498 ball head.

If this doesn't work out I will plan to use the Wimberley plate on a higher end ball head, but I don't want the $300+ answer unless it is necessary.

Dave