Hello! I did an overdraw of some of the heads. I will note some of the issues which I saw. Sorry for not going though each one separately.
When you draw the same head from multiple sides, make sure to make each head parallel to the other. For instance, the top part of inner circle in head 1 and head 2 are not the same. This will confuse you, so keep that in mind by drawing a line through your first head. Also make sure to draw the inner circle at the center on profiles ( in 1 I can see the inner circle being at the bottom right side instead ). This can also confuse u as u learn more about the planes of the head.
Also, at view from below, in the upper line, u can see that the chin has a bottom plane. U need to have it consistent along the heads ( can be tricky I also struggle with such views ).
Also, when u do the ellipse, make sure to make it fit to the perspective as well. Its a bit of nitpicking at first but as u draw the head more volumetrically, you will encounter such thing a lot at 3/4 views. This also brings another issue with the line of symmetry. ( There are some other heads that got the same issue like head 5, sry again for not going though all of em ;-; )
Another thing I recommend for now is to try not to narrow down the face too much. Widen the bottom chin a bit and dont make the arcs bend a lot inwards.
If u want to spend a couple hours, I think his videos are a goldmine on making loomis heads. Else, just go straightforward and study Loomis's book on drawing hands and heads. Its free on google. I'd go and try draw his heads by reference, even trace them in case u cant copy them properly ( for now ).
Overall, from your previous images, I can see some very good progress overall. Keep up the progress and never stop studying!
