I wouldn't worry about matching their parameters so much as I would matching their look. Establish your scale first. This holds especially true when trying to scale rigged characters with simulations and dynamics involved. For sanity sake, avoid it if you can.

That said, you could probably write an expression to adjust the relevant attributes based on your character's world-space bounding box to try and maintain the same relative look. However unless there is a compelling reason to do this for a given shot, I would avoid it.

-Modulok-