I recommend against the head lamp. I used them in mountaineering, and they shine light at whatever you are looking at -- imagine looking up at your subject and blinding her during her number! The book light is a better solution.
In the October issue of Artist's Magazine on page 34, in an article about Robert Armetta, is pictured his premixed palette recipes. I know for the life of me I have also seen, within the last day or so, an image of a palette with several skin tones premixed, but I can not locate it. But I found this online:
http://2.bp.blogspot.com/_Eiwce13X73...0/PALETTE+.JPG It shows the artist's palette with anticipated colors and values all premixed. I could see something like this being of great value in your situation!
Addendum:
This is what I was looking for to show premixed colors:
http://www.rexart.com/art-supplies-b...matters_lg.gif