Plus, he sits in China(if he put the correct location in his profile), that means you seldom get your optimum level by chinese controllers.
Further I have to agree with some of the other posters - flying an aircraft without knowing it's capabilities(at least!!! as a captain) is kind of - new generation
.
Good luck, for this trip and your further career, you might need it.
EDIT: Having an other read thru your post - I am not flying your aircraft type. You should have optimum altitude tables(if not go for your maximum altitude tables and deduct 2000-4000 feet, should bring you close to optimum). If you don't make it with this levels you won't make it at all.