If the GL is going that badly, maybe it is a good idea to change, imo. My sister's dog ended up hating it so much, they would just show it to him, if he was misbehaving, and he'd do whatever they said, just so he wouldn't have to put it on (not saying this way right, just an example).
We use a prong, which when used correctly, works well. If you can try Cary's method, I think that would be perfect.
