Difficult question.
Are you bacon or are you eggs?
The chicken is involved, but the pig is committed.
Really though, here is my question for you:
I personally find it odd to tell a litvish woman to shave her head, since it is not a din, or even a chumrah, but merely a minhag of the chassidim (I think).
But, if you trust this person, and trust his daas torah, and he thinks it is a good idea for you to do it, then I reckon you should do it.
If you don’t, I don’t know why you go to him.
Maybe I’m wrong, maybe it is more nuanced than that. But it’s a starting point for thinking about it.