Gilbert,
I haven;t experienced any problems with the legs nor the center column. Having said that, there was once when I had the legs down really low, but with a Canon 1Ds and Canon EF70-200LIS lens, it was giving in a little, but I tighten up the rings and it was fine after that, I have to say i was very low and it was in a very odd low position...no :-( i didn't get the shot I was looking for!
Marcus,
Cable release, isn't attached into the shutter, ( I obviously dont have the 503CWD) only the 503CW, so I am guessing (thats a bit dangerous)
Peter,
the Ultimate ball looks like an awesome head - and I am sure the Carbon One are great legs too, I didn't mean to knock any other brands with my Gitzo
and thanks for the link to Clear Sight
Henrik