Sorry, I have been away over the holiday weekend - had a lovely trip to Paris - I spent 3 hours in the Musée d'Orsay, also I visited Delacroix's studio, and spent a day in the Louvre. I visited the Pantheon to see the paintings there, and also the Picasso Museum and the Modern Art Museum at the Centre Pompidou (only bothered with the top floor - 1914-1950 or so). Needless to say, I dreamed of paintings every night.....
I love drawing in pen as well - and after much difficulty, I found that the problem was the pens. Pre-industrial artists used feather quills, which are flexible, and give a wide variation in line, enabling a very delicate line to be achieved - a hairline. I searched long for a pen that would give me this type of control and line quality.
Eventually, I found some steel pens that are very good indeed - handmade Japanese manga pens. These are made by Nikko - (TACHIKAWA) I ordered a complete set online. (A Google trawl will locate them online.... key word's something like "Nikko, tachikawa manga pens.") In particular, I like using their "G" pen - it gives a wide variation in line, from very heavy to fine. Some of the nibs also let you draw with an ultra fine line - approaching the hairline fineness that can be achieved with the "thorn" that can be cut delicately on the edge of the nib of a quill pen. With this fine metal nib, it is possible to emulate the difficult lines such as those found on pg 30 in the Michelangelo drawing in Drawing Lessons from the Masters by Beverly Hale.
I was trained to cut a quill pen by a Jewish Scribe - I wrote down all the instructions step by step - perhaps I should scan the page and post it here.......
Regarding what I said about sight size - let me qualify it - I abandoned excessive use of sight size. I do use a plumbline very occasionally when I have trouble, and use it sparingly to check the angles after I have put in my construction lines by eye. This is more akin to Sargent's method - placing the model next to the canvas, or slightly behind it, and then stepping back, and then forwards to draw - but without detailed tight measuring. This is, I suppose, correctly to be called sight size, although it does allow for the flexibility that you can change scales, or work from a drawing board on your lap. Like you, I am on a steep learning curve, and find out new things every day. I have learned a lot from this forum already.....
Evan.