I've just got a small update today. I've got the metallics on my front rank of Marauders.
The silver is Boltgun Metal with a Black Ink wash, while the gold is Tin Bitz, then Brazen Brass with some Burnished Gold highlights. I washed it with Chestnut, Brown and Purple Ink.
Unfortunately, I haven't completed them in time for the start of the Nemesis campaign but I hope to have them finished in time for the end!