First up, thanks for the honest words, l really appreciate that 
You are right, it was a questionable choice that had to be made because nothing else would fit there. On the other hand, it complements this part of Artakha’s description:
because it’s a flat surface you can put some custom rune stickers onto
It’s not exactly right, but very close. The curve is in the right place, but the actual human spine has another one right under it
That’s just my artistic choice 
Yes, that’s correct. These should be silver, but I’m not gonna reshoot every single picture, unless They ask me do so 