Is there a specific way to install a zipper on a fursuit head?

I am making a balaclava-based fursuit head- I know that once I fur it, I won't be able to pull it over my head because fur doesn't stretch like the balaclava material. So I'm going to add a hidden zipper to the back of the head.
Should the zipper JUST be in the neck, or should it extend to the back of the head as well?
I know this may sound like a frivolous question, but is there a specific way I should install it if it has to extend to the back of the head and the neck?

Thank you for your time!