Gaston, many thanks for the insightful reaction.
My questionis it possible to understand when these heavyweight participants ' are'making a difference' (or perhaps even better, if they are just about to drive price in a specific direction), only by taking a look at price action, or does one need to have access to additional info (e.g. across-the board-volume, market depth, order placement, etc)?
There is a fantastic article by Merlin somewhere (wish I could find it), in which he says that the best way to develop a system is to find a pattern/phenomenon that you think...