Sorry, I have just thought that you will need to consider the location of the 3rd pin in relation to the tail to ensure you get a good range of movement on the scales, that pin is going to hit the tail somewhere by the looks. It might be worthwhile mocking it up with card first to see what happens. I did that when I was designing a razor and it helped me a lot with the shape, though I didn't do that with the scales I left them to someone else.