Is there a formulation that I can use to make a material preset that will add an eye reflection to Genesis when using a Gen 4 texture (either a V4 or M4 texture)?
Usually what people do is put in a reflection map on the cornea. I'm not sure, but I'm 90% sure that the V4 and V5 and Genesis eye UVS are identical...
Although the UVs are the same, Genesis lacks the eye surface material of the fourth generation figures (which was a transparent overlay that could be used to catch highlights and reflections without disturbing the actual textures).
That's right! Forgot about that... Genesis has a few less material zones than does V4. Which actually makes things easier to manage...
I've found I get better results adding reflections to the sclera rather than the cornea. Strange but true. The trick is not to use too high a reflection (unless you want metallic eyeball syndrome). If you're using the UberSurface shaders, also look into using the Fresnel so the reflection doesn't obscure the eyes too much.