During this project I discovered some amazing new time saving sculpting tools- the digital camera, the scanner, the printer and my lightbox. At the end of each day I would take pics of the mask, print them out in black and white, and sketch changes over them I'd want to make the next day. This helped me stay focused and saved hours of needless fiddling.
I also found that if I took pics of the mask on one side and then kept the tripod and the stand in one place, I could spin the stand around and get a picture of the other side of the mask that when flipped over, would line up very closely to the first. Then I would print out both pictures, trace around the major lines in red, flip one picture over and then lay them down on my lightbox to see any significant differences between the two sides. This was very helpful if one feature looked "right" one one side but "off" on the other, I could tell right away what the difference was.
So I had a sculpture I liked after only twenty one hours of work, which is far as I'm concerned is unprecedented.
Next, casting and painting the mask!