Performers who came to NY on an O-1B visa - what proof actually worked?

A question for any actors, dancers, singers or designers here who have worked in New York on an O-1B (artists) visa. A colleague of mine from abroad has played lead roles in a few well-reviewed productions at home and is wondering what really counted as evidence that a production has a distinguished reputation - were regional theatre reviews and festival posters enough, or did she need coverage in major national press for each show? Also, did anyone have to get an advisory opinion from a union or peer group before filing, and roughly how long did everything take from start to approval? Any firsthand experience would be a huge help.