Really tight...

I finally did a duct tape pattern on my head! It looks great, but when I went to put the head on again, it fit like a glove, which is great, but bad, because it smashes my glasses to my face on the way in (it smudges them badly!). I think it's because the duct tape on the back of the head doesn't really allow for stretch. It did not have this problem beforehand.

I figure I can install a zipper up the back so the fur isn't so tight, but Bryndle is getting a hairstyle, so how would this work?

Below is a link to her reference sheet so you can see what I mean.
http://www.furaffinity.net/view/10373805/

Also, how much kanekalon (and what specific color) would I need for that kind of hair?

Thanks everyone! :)