Hi Les, in regards to my painting technique, I would describe it as oil washes over acrylics.
What I do is I paint the basic underlying skin tones (base colour, highlights and shadows) in acrylics. Typically I'll use a combination of Josonja Flesh Tone, and a dab of red and blue to create a slightly purple flesh tone as the base colour. I blend and feather the transition zones roughly and then I give the acrylics a day to dry. When fully dry I then start to apply the oil washes.
This is made up of approximately 10 drops of white spirits to each small amount of oil paint to create a rather dilute wash. For this figure I used a combination of Titanium White, Naples yellow, Burnt Sienna, Carmine Red and Prussian Blue. I then create a separate highlight wash which includes some of the basic oil wash colour with a bit more white and Naples yellow added and apply some additional washes on the highlighted areas. For deeper shadows I add a touch of Burnt Umber to the Basic wash mix. The 5 o'clock shadow is made by applying a very dilute wash of Prussian Blue.
I apply numerous washes as the amount of paint in each wash is very small. The idea is to gradually build up depth of colour and to create some very smooth transitions. The white spirits evaporate away quickly leaving a very even flat finish.
Once I'm satisfied with the coverage of the oil washes, I tend to go back and do some highlighting with acrylics just to tidy up. This explanation isn't exactly comprehensive but hopefully it answers your question.