Is occipital reduction in the back of the head safe & how much reduction is expected? (Photos)

I was thinking of doing a occipital reduction in the back of the head but I just have a few questions: Is it safe? I have not found a lot of info about this online except from one clinic but I'd like nuanced answer because it does seem like a big procedure. What is the "worst" outcome if it goes wrong? And also how much reduction is expected from this ? I have a big head with a noticable occipital bone that sticks out so that is why I am asking.