Ahhh... I think I have it now. You have to reduce / enlarge features with keyframes, rather than by editing the skeleton in edit mode. Very clever. Thank you for schooling me on this trick! Although I have to needle Reallusion a bit, as this is very counter-intuitative and almost feels like I'm tricking the program, rather than following a design guideline.
Regadless, I think I can work with this method. Much appreciated.