How much of book 3 is adapted by the show?

I've watched past episode 5, I've read that episodes 6 onwards cover both the beginning parts of book 2 and 3. I've read up to about page 350 of book 2 but have been slow going because every time the pov changes to Zhang Beihai I want to eat nails. How far do I have to get into book 3 before I can continue watching without spoilers?