Two things to remember when using hide glue: always "tooth" the surface to ensure a good bond, and, depending on the humidity, you may need more than 24 hours for it to cure properly.
I just tried removing a bamboo backing from one of my bows. It was glued with hide glue. That backing is not coming off ! Even with heat, it won't come off in a strip. The only way it's coming off is to rasp it down.
I should mention, I only use hide glus made from deer hide. I've never tried the Knox gelatin.