Used the adhesive remover but it was still very difficult for me to slide the card in the battery. I realized that, at least for me, that you have to start from one of the corners and use the card and a spudger to pull the battery out. Once I figured that out, it was pretty easy to do the rest of the cells with the adhesive remover.

Fantastic guide! Makes no sense why Apple makes such a simple thing so hard. Almost thought I broke something.