There's a difference between shading and light source. You can still shade it the same way and have a different source for the light. I even painted out exactly which, and only this part of, the shading I was using as an example.

Vaderios' renders do a good job of showing that "deep gradings" don't occur unless the object in question is close to being paper thin. The transition phase from light to dark has a roughly fixed depth based on the shape and type of material.

And I know it's unfinished. However I also know that "unfinished" may also mean "close to final look" and figured any criticism would still be relevant to the parts you hadn't changed.