have russian mig drivers flying for the north ever been formally reported/documented.?
I've read both yes and no. I think the VPAF as claimed they never flew combat missions while the Russians have said otherwise. So who knows.
This book is an excellent account of the air-to-air war in Vietnam and the author says that the Vietnamese were very nationalistic when it came to flying their aircraft to defend the homeland and that reports of Russian pilots doing some of the fighting are not reliable. He relies on quite a bit of declassified US info that included info about communications intercepts, with the GCI dependent VPAF it would pretty authoritative on the subject.