I should look through my masks and take pictures of them. Perhaps they can be of help to you. I own all of the masks on second row (in the spoiler on the topic post) in addition to that small golden one + a few others I'm not sure about (you have done two of them already). EDIT: You are planning on doing this guy's mask, right? Because I have his mask and Lewa's from the same area if you need reference images. Kopaka Nuva was the first Bionicle I owned, so he is special to me.
Yes, as Alcom so accurately pointed out, I do plan to do all of them, but the Nuva masks are so fluid looking I have put them off. The smoothness makes them look cool, but really hard to shade. My laziness kicks in at that point and they don't get done.
Thanks about your offer to photo them. I own at least one color of every mask that was available on Bricklink. The ones I didn't have I ordered a while back, so thanks, but no thanks. however, if you have the red-and-black Kiril, please do photo that one. I am still dubious over the coloring and only have the yellow version.