Matte and flat paints,
but if you need to use a gloss becouse you can only find the colour you want in gloss then use gloss (or satin) once you are finished you want to coat the whole helmet in a Dull coat any way so that will even out the sheen levels
I had the same problem with my paint color choices. The olive was a satin, but the burgundy was gloss. After clear coating the whole kit with a flat clear, all the colors look the same as far as finish goes.