I'm thinking you've got this nailed except for perhaps the right side. looks a bit blurred to me and I can see lines instead of a gradual gradiant. makes it sort of look like there are ridges. hope I explained that.
anyways that's what it looks like to me. and I must say it is and exceptional piece.
ahhh I see. I was really hoping that you could tell me the method to get those ridges in 3d shape. agree with you on the imperfections bit, totally, that's what really makes artwork sing and resonate for me.