Hairworks Binding?

How exactly does hairWorks bind to the grow geometry?
According to the resources I could find online, it suggests that the binding is dependent on the joint weighting that the grow geometry has. I tested adding a cluster deformation to the geometry to see if the hair would still follow and it appears it does not.

Is it only limited to the joint weighting and not necessarily the geometry deformation itself?
What about morph targets will the hair bind properly when there is a morph target?

Is there a joint limit for hairworks export?