Drag and drop the shader into your shelf or copy it inside the shelf folder 
(C:\Users\*user*\Documents\Substance Painter\shelf\shaders)

Shader uses Diffuse    (sRGB8), 
            Normal     (RGB16F), 
            Height     (L16F), 
            Specular   (L16), 
            Glossiness (L8), 
	    Metallic   (L8), 
            User0      (L8),     (Envmap mask)
            User1      (L8)      (Color mask)

Shader settings:

Envmap reflection uses either user0 or Specular channel (default) as mask, 
depending on if the "Use Specular Channel" is checked in shader parameters.

Glossiness uses either the slider (default) or glossiness channel depending 
on "Use Glossiness Channel"

Metallic channel controls diffuse specular tint (tints the specular 
reflection with diffuse color). Enabled in shader settings.

User1 channel is Color mask, used for tintable props.


GLOSS WIZARD

Creates Glossiness and Envmap mask from Specular or Roughness channels.
Drag the .sbsar into your shelf, export as a filter.

Usage:
Drag the wizard on the top of your layer stack, but below AO if you have any.
Note that your project needs to have the Glossiness and User0 (Envmap mask) 
channels for it to work.