His legal experience.

I would like to recommand people DIY if they know GC application process well or they have done good research in this filed. Sometimes we made simple mistakes because of lack of this experience.

Can you find some Chinese in your school or field who are in the similar situation as yours, and did Eb1-a before? You can DIY of cause, you know yourself more than anyone else. If this Eb1-a is not very critical to your life in US, just try your ability.