12 years ago I participated in a memorable workshop given by Susana Miller (who is often credited with introducing the term "milonguero style", and who was to a considerable extent responsible for this style of tango dancing to spread in the US). Susana talked a lot about how people misinterpret the lean of apilado and how Gavito stage-tango videos completely misrepresent the extent of the lean, and then spent almost half the class just walking around and hugging leaders to show just how much lean is involved in apilado. In short: very very little: there is a real hug, and the two axes are not completely independent, but the follower is not leaning as much as to fall ahead if the leader suddenly got vaporized.