1:1 sounds nice heh. did a ferrari interior and they wanted it 10:1 that was kinda rough. so I just painted it red :p. artistic liscense I say. loved it :)
1:1 should be easy enough to get right though.
though from what Im seeing; they want a satin finish gunmetal. since thats gunmetal mixed with flat base. might just try baby powder or something; read somewhere that would make tamiya paints flat. I might be making that up.