i use oils on all scales for uniforms and flesh, and i do it the old fashion way. lets say i am doing a German soldat, i paint the uniform in acrylic Field Grey and the flesh in acrylic such as Jo sana or another good brand(i like to stay away from Tamiya acrylic, it has phermaldahyde and can effect the oil paint) and let it cure for twenty four hours. next day, i mix up a shade of Field Grey in oil and from this i mix up several darker shades for the different shades of shadows and several lighter shades for the different shades of highlights and lightly apply these over the acrylic undercoat blending the edges of where highlight and shadow meet. the face is done in the same way. i learned this style of painting from Shep Payne at a seminar he gave a course at over twenty years ago. this info is a light overview of the style, i would suggest you pick up his book: How to paint Military figures; by Shep Payne. also you will want to get a basic color wheel to learn how to mix the oils for different colors and some good quality red sable brushes. and remember to be patient and practice makes perfect.......good luck