Bobd wrote on 03/08/12 at 09:50:02:

Both. You are balancing the mixture: You affect air without changing fuel. After balancing, both cylinders will have the same AFR.

First you balance using the linkage, at a couple of thousand rpms. The bleeders will have no significance there. After this, you balance at idle using the bleeders. I tend to aim for as little bleeding as possible, closing one side instead of opening the other. If rpm gets too low or high, change the idle cell (ie. do not use bleeders for idle speed).