Has anyone ever attempted to add "flattening powders" to hobby enamels like Model Master enamels or Floquil enamels to "dull down" the glossy paints to make them more semi-gloss or flat?I haven't done it or tried it and the amount I expect would be so small...I'm not sure how to measure that out "per ounce or half ounce".Then again I wouldn't know what brand to use if there was one that does work or is recommended? So....just asking if anyone has thought about this or tried it?