As a rule Chuwi is not providing any support whatsoever for doing things that will change the setup (relative to what they did with it in their factory).
Even if you wouldn't need such help, they're celebrating Chinese New Year now, and are unreachable.
Your only chance to get some info is that a user with experience of resizing Android partition notices your post.
Alas, with single OS Hi8Pro, I am not that user. Good luck!