No need to add multiple copies of the vss prop.   The shader rules will apply to all figures that have the same materials.  But I suppose there's no way then to make changes to only one figure (for example have one with wet skin and one with dry).   I'd like to find that out too.

I usually also set SSS to 0.2 or 0.3 so I don't get that much of a reddish tone.