It's really nice. Very informing, and teaches others who struggle what they are doing wrong, and how they can improve.
My only complaints are, that the shoulders are to low. Need to be brought up higher. The way you have them placed is making the neck seem to long. The eyebrows are a bit to far up away from the eyes. I think they should be brought down a little bit.
I can link you to a self portrait study that i did, that still has all of my placement lines and how I set things up if you want. I think it will help you further your understanding of the head. (Granted it is about a year old now.)