This'll be a tricky one mate. You'll probably need someone who's actually got the statue or at least access to the statue to give advice cos it's hard enough matching when you have the piece yourself let alone from photos.
I've just finished a custom Thor head and it took me a couple of tries to get it right:
That said there are plenty of better painters than me out there so hopefully one of them can chime in.
Your other option is to get some plastic spoons and paint them up as testers until you get one with a similar finish.
Good luck!