/ic/ - Artwork/Critique

I don't think I'm understanding Loomis.
I follow the steps in pick related, but there are some things I just don't get:
-According to the book, the hairline is halfway through the top of the circle and the brow line, but that's not true, on some art forum it said that it was 2/3 of the height of the circle, so I just try to guess where the hariline is and build from there because I have no other way to know with certainty
-The way Loomis cuts the sides of the circle, I don't think he ever said how big the cut should be, so I just guess it
-In a 3/4 view, I also just guess where the middle line goes according to my reference because I don't have any way to know for sure
-The position of the eyes underneath the browline, I also kind of just guess it is the half point of the entire face and be done with it

I'll post an example of my shit