I have the 7d with the sigma 10-20 on the merlin and I have it pretty much balanced. The buble is perfect and the drop time is about 1 sec. The problem I have is that when I have it on the Tripod docking station it always turns to the left and then it stops there but still the buble is in the middle. I do find that it sways when I use it sugestin that it is a little botton heavy but the drop time is 1 sec.
Any thoughts
Sebastian