Check the AUM for shader collections. You can examine the code. There are few left here working on great shader stuff.
With bumpmaps you will want a high res version of a model on 3dsmax to generate the normal map from, as the idea is the 2d normal map is holds greater detail then the low poly mesh.

I realize I haven't answered anything, but it's the best answers I have for the subject. I recently had a forum member make amazing shaders on a project of mine and I was lost trying to just read and follow the shader code. You will need a higher level math and math concepts.

EDIT: I know it's getting to sound like a broken record. But most the shader experts I asked for help from these last months have simply said - just use Unity