I don't know much about gonial width, but I think that would be something like implants. When you say jaw angularity, what are you referring to? It looks like you carry weight in your face naturally, and it's possible losing weight could increase that. You're on the right track with CCW, but it wouldn't just be BSSO if you wanted that. That would be double jaw. If you want BSSO only, and I do think this could be an option in your case, you'd probably have to extract two lower premolars and then advance the lower jaw forward. This would likely give the illusion of lengthening the chin, too, without having to touch it. I also think no surgery at all is a good option. You look fine as is.
