I wish I had a picture of a painting I'm working on now (it's almost finished). This is what I do and I think this is what Karin is talking about. For the exact fleshtone, I decide what the undertone of the skin is. If it is a cool undertone, I add blue, if it is a warm undertone, I use green.
Here is my mixture of fleshtone: flake white, add cadmium red light, then cadmium yellow light, then to warm up the color, I add yellow ochre, and last either prussian blue or phthalo green (very very small amount) to grey the color so it will not be so orange. Flake white and yellow ochre are opaque colors and cannot be used as a glaze because you will lose any shading underneath. If you use a dry brush and add the fleshtone on top of the underpaint (scumble), you will not lose the shading underneath.
I've always used a dry brush and I am pleased with the results. I used to use glazes all the time until I ruined a commission because the paint underneath the glaze disolved. Because of Karin, I am trying glazes again and so far so good. Karin, you're just going to have to make a video!
Hope this helps,
Renee