I have found that using acrylic paints gives a better Matt finish and is much easier to use for weathering than enamel or oil based paints, Acrylics are water based so can be easily thinned or mixed, they dont smell as bad in use as they are free of toxic chemicals and they dry quicker. I do use Humbrol Enamels for underframes. I have been using `All Purpose Acrylic Craft Paint' bought cheaply at a local book/craft shop in Poole, for some time now with reasonable results. You can also use Talcum powder to transform glossy enamels into a matt finish by lightly sprinkling talc over the wet enamel paint the talc can also be used in several light coats to produce a slightly roughened finish on Flat/Smooth surfaces and will fractionally lighten the hue giving a sun bleached appearance, the excess is simply hoovered off once the piece is completely dry. Enamel paint can take longer to completely dry when talc has been used. The whole model is then `sealed' with a light spray of clear satin varnish, and a final weathering coat can be applied once the varnish sealing coat has fully dried.