This was a tough one, as following the Buglips the Goblin official order of L2PKs (1,2,4,5,3) we only have Kit 1's metal method (tm Doug Marks). Which is really the only way I ever painted metallics, and it's pretty prehistoric. Other than that I'm ok with how Bertokk came out, pretty fast for me - about three sessions of two hours each.
http://www.reapermini.com/forum/index.php?/topic/46281-opengroup-wip-l2pk4/?p=657486'>WIP here.