Definitely J1!!!!!!

Definitely go for J1. This way, you total time in US will be 3 years (J1) + 6 years (H1). This will maximize your chances of staying here since most people doing biomedical research will get green card during this period. However, if you come as H1, you will only be able to stay here for 6 years. Time goes by fast and GC is taking a long time nowadays. It is very easty to get a J1 waiver from Chinese government. And you salary is a little too low. Ask your boss to pay you the NIH standard salary, which should be somewhere between 36000 to 40000 in your case, depending on previous experience. Good luck.