Right, the rad cage is supposedly meant to improve things on large cassettes by altering the way the upper jockey wheel tracks across the cassette, it supposedly does this by offsetting the jockey wheel axle from the lower cage’s pivot point.
From what i can actually see, the pivot location of the lower cage is determined by the fixing point in the knuckle, to be specific, the mounting axle for the roller bearing which is part of the clutch mechanism. The rad cage, hence jockey wheel attaches to this same point as the shimano cage, it doesn’t offset the pivot point or the top jockey form this pivot point in a different way to the standard shimano cage.
What does the RAD cage actually do?