In most cases, I trash the Firefly shaders and create a new Superfly shader from the ground up.  I've developed a workflow incorporating SSS in all my character renders, a system I created to optimize their skin textures.  The creature below is an example of that.

The following image is a reworked OBJ set freebie I picked up from ShareCG.  Everything has Superfly shaders that I created.  The dotted curtains, lampshades, and comforter are all procedural materials.