Well Harry you have even more of my respect than before. This was an extremely difficult technique to do. It may have been complicated by using a previously painted canvas. The charcoal wasn't grabbing the surface. I understand fully that a light touch is needed. It took me a bit trial and error to get the right brush. What seemed a soft enough brush turned out to be way too stiff.
It didn't help to have Admissions call me in the middle of painting wanting to talk about transfer credits. While I listened to the Admissions officer I did my best to keep painting before everything dried.
In spite of the difficulties it was a good exercise and I plan to do it again but with a fresh canvas, gesso with a sponge roller to give more tooth for the charcoal, choose my brushes before I start LOL.
I was in a rush to try it but sometimes it's a way to get started- show no fear.
Funny I can see where and how I lost depth around the neck. Hmm I wish I could recognize these things earlier. Anyway below are the results.
reference photo, charcoal over painted, oil over charcoal