Great job on keeping with the studies. I really like that anime face 😃
As for head construction, what I notice is that the side plane size is not consistently 2/3rds of the sphere and is not “cutting the sphere” (for example when seeing the sphere head on, it would look like the sides are cut)
In some, the proportions are off on the brow line/nose line/chin line. Remember to center the brow line in the side plane to help you out and if the side plane is close to 2/3rd, the bottom of it, while keeping the angles right, will correspond to typical nose base line, once you have that vertical distance between brows and nose you can get the other two correctly
Another thing to consider is the contour of the malar rythm which Marc simplifies as going from the center of the side plane to the lateral edge of the chin. Finally, the chin is not really very pointy, usually its width will correspond to the width of the mouth (an artistic simplification) but will be very pointy in stylized art like anime
I hope some of my observations make sense for you and help you along the way
Cheers and keep it up!
