Well you are successfully doing things. You are indeed set up to copy shaders into four zones from four templates. 

I just don't understand why. Are you planning to manage hundreds of sets of wings simultaneously? I get that you're not ready to explain why you're doing this, but I can't explain what you should be doing if I don't know what you're trying to do.

You plan to copy the shaders from the wings into the VSS control prop, so that you can press synchronize and copy them back to the wings. Why? VSS is not going to magically make them look better. The shader decides how the object looks, not VSS. Asking VSS to copy the shader into the wings that you just manually copied out of the wings is going to leave you exactly where you started. If the point is the journey, well, OK. You're done already. You did all the steps to prepare to copy a shader from the control prop to the wings. All that remains is to get the four shaders into the control prop.

So I would go to each of the wing materials, and save it to the library temporarily. This does two things: let's you recover from mistakes, and let's you load them into VSS.

Next: Load each into the desired VSS template material.

To turn them into proper templates, go into each image map and set the image to None.

Then press the Auto Rename Images button to give the images names.

If they all rename to sensible things (which you should review) then you're ready. If one of them does not rename, you have  problem. We would address that if we run into it, otherwise that will just be a lot of confusing information for no purpose.

Sensible things are: Color Map for the diffuse color, or anything that plugs into a Diffuse node, or a Clay node. Specular Map for the Specular_Color, or anything that plugs into the similar channel of a Specular, Blinn, Glossy, or Anisotropic node. Bump Map goes into Bump. Displacement Map goes into Displacement. Transparency Map goes into Transparency. 

Once a template has good names for the images, when you synchronize, VSS will examine the target material, figure out which map is which, and plug those into the template shader getting copied onto the target.

If a template shader has a named image in it, and no obvious image exists in the target, VSS will replace the image with whatever is plugged into the Image_Map Background parameter. This is a trick that lets a template work with or without a given image map. For example, the VSS skin shader substitutes a Turbulence node for bump if the target has no Bump Map.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)