I hope you all won't mind if I go off-topic and discuss the mix.mm1.txt script again. I'm working really hard to get my head around how to implement.

My objective is to layer colours for eyeshadow, with eye-liner being the last eye-colour. I may or may not want shine for one or more of the colours.

I had actually typed a whole slew of questions but then I read and re-read your description again, and suddenly it gelled:

**# Main AGC objects first
colourMap = ImageMap().labelled("Color Map")
bumpMap = ImageMap(Background = setTurb).labelled("Bump Map")
skin = CSB(.5 * AGC(colourMap), .25, .01 * bumpMap)
 

Makeup colours

Blusher = CSB(AGC(IColor(237, 154, 130)), 1, 0)
highLight = CSB(AGC(IColor(196, 236, 220)), 1, 0)
eyeShadowA = CSB(AGC(IColor(223, 170, 137)), 1, 0)
eyeShadowB = CSB(AGC(IColor(27, 82, 60)), 1, 0)
eyeLids = CSB(AGC(IColor(16, 60, 52)), 1, 0)
eyeLiner = CSB(AGC(IColor(33, 0, 0)), 1, 0)
lipStick = CSB(AGC(IColor(223, 28, 0)), .7, .03 * bumpMap)
 
nailClr = CSB(AGC(IColor(138, 0, 17)), 1, 0)
 
blusherMask = ImageMap().labelled("Blusher Mask")
hiLightMask = ImageMap().labelled("EyeColour A Mask")
eyeShadAMask = ImageMap().labelled("EyeColour A Mask")
eyeShadBMask = ImageMap().labelled("EyeColour B Mask")
eyeLidsMask = ImageMap().labelled("EyeLid Mask")
eyeLinerMask = ImageMap().labelled("Eyeliner Mask")
lipStickMask = ImageMap().labelled("Lips Mask")
 
skinBlusher = skin.mix(Blusher, blusherMask * .5)
BlusherHilight = skinBlusher.mix(highLight, hiLightMask * .3)
HilightEyeshadA = BlusherHilight.mix(eyeShadowA, eyeShadAMask * .4)
EyeshadAEyeshadB = HilightEyeshadA.mix(eyeShadowB, eyeShadBMask * .6)
EyeshadBEyelids = EyeshadAEyeshadB.mix(eyeLids, eyeLidsMask * .9)
EyelidsEyeliner = EyeshadBEyelids.mix(eyeLiner, eyeLinerMask )
MadeupFace = EyelidsEyeliner.mix(lipStick, lipStickMask * .5)
 
limbsMask = ImageMap().labelled("Limbs Mask")
skinNails = skin.mix(nailClr, limbsMask)
 
nipsMask = ImageMap().labelled("Nipples Mask")
skinNips = skin.mix(skin, nipsMask)
 
outputs += [
  "-Skin", CSBSurface(skin),
  "-SkinNips", CSBSurface(skinNips),
  "-SkinNails", CSBSurface(skinNails),
  "-ShadowLipstick", CSBSurface(MadeupFace),
]**

Am I getting close, here?

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

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[it is clear that humans have contempt for that which they do not understand] 

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