When I work on a portrait using angles I basically stay on the edge of the hair/head. I incorporate negative space between the shoulders and neck very early on in the process along with vertical measure lines. The proportions for me live or die in the first two to five minutes of drawing.
The only time, early on in the process, that I venture into the interior of the head is with the shape of the hair. Once I have the shape of the hair looking like the model’s hair that should go a long way in capturing the likeness.
The features are then basically drawn using a bit of continuous line.
What I have found over the years is that if you only use one technique in isolation you limit how you see things. That is why all of my first DVD’s were titled the layered approach. I use multiple techniques to solve the problem of getting a portrait correct, not just the angles.
Hope this helps,