Trying to further my understanding of anatomy, starting with faces

Greatest work on your range of forms and spaces and forces of your heads, faces and expressions. It's good that you're self-transitioning yourself to starting off the more than slower but fully carefuller style of realistic portrait sketching, but the gestures and relationships here are still too rigidest but stiltedest to me yet. Would you like to go ahead with 18 minutes of 2 minute face sketches, all sketched out underhandedly still, but all done with your non-dominant hand?

The reason why you can and will work fastest is because of this fact: if you could draw more slowest, then you can and shall work at the most top of speeds with gesture drawings, even if you need 15 minutes of 5 minute blind contours, to sharpen your bonds of L-mode and R-mode, by including R over L.

For most details, please look into Drawing From The Right Side of the Brain, and Drawing From The Artist Within. The latter is still most extremely essential, because you could and would go for the 30-60 minutes of 1 minute idea sketches.

My hat's off to you.