It seems you know nothing about J1 waver. Actually, each No Objection letter has a special case number on it and it is only for your current J1 project. and your plan sounds good but actually it is not practicable. because once your current j1 ends and you return to china, you have to stay there for two years before the US embassy give your another J visa or H visa.
so I think you should extend your current for half or one year. it is possible now. and you should ask your boss to help you. now the department of state of USA has new policy about J1, the maximum time is five years. and one of my friend just ask her international office to request a extension from us department of state. you need your boss to help you do this. and the international office of your school need consult the offical of the department of state to file a special request. anyway, it is not easy but possible. that is a hope. so extension is a better way to go.
just some suggestion for your reference.
God bless and good luck!