your need to cover the suit in latex to seal it for painting if its exposed or the foam will absorb all the paint, look on the predator forums they make lots of full body suits. if the muscle suit is under clothing you don't need to worry. as for skin tone itself i only know white european skin, you needs lots of white a small dab of red small dab of green and a small dab of yellow, add more green/yellow/red depending on your own skin colour but only small amounts