Wow! This is helpful. Were you working from a photograph? Or drawing from memory? What make of pen is that? I've been using a Safari ink pen with extra fine nib and archival sepia ink. I like it so far, but up strokes are a challenge. Have you seen the Rembrandt self portrait that is done all in black lines with cross hatching? I think it is an etching. I'll see if I can find it on the net and add it to this reply. Thanks for your posts. More, please, when you get time.

http://www.rembrandtpainting.net/rembrandt_self_portraits.htm
The images came from this link. It has a good discussion at the end.