Is there a way of getting the horizontal proportions? Same way you have explained the halves and thirds, but for the width of the face so we don't end up with faces that are, in my case, too narrow. I have thought about this because I don't know where would be a correct position to draw the temple in my sketches to form the temporal fossa. Thank you.

Some more difficult than others but I feel good about these, learned a lot. I don't want to bother too much for a critique as I feel I understand the concepts pretty well, just need more mileage. But if anything, I'm struggling with finding the right head orientation (tilt and major axis for the ellipse) as if I don't get these foundational lines right, the rest falls apart. I'm not sure where I'm supposed to look at to deduce these; more often than not it's only when i start to place the jaw, the brow line, etc that I realize these angles were wrong and I'm starting over.

Very difficult! Foreshortening is no joke and more often than not i would underestimate it

Practice practice practice

Practice from imagination. I feel that I understand the head construction a lot better when manipulating in 3D like this.

I don't really understand the last part about the ellipse and the equator line. It doesn't make sense. How does that help you with the proportions and perspective?