No doubt the schwarze Hefte will be an interesting read, but what of the contents of GA16? Looking through the contents listed by Dahlstrom on pg254 of The Heidegger Dictionary it would seem to hold a few clues as well, for example: (III) numerous short entries from his time as rector, "many clearly establishing Heidegger's enthusiastic support for national Socialism)"; (VI) 1950-1 "entries acknowledging his 'political error' and a sense of 'shame for what transpired against Jews' yet also repeatedly denying accusations of anti-Semitism, mistreatment of Husserl or membership in the SA or SS."
Oddly this also contains 1955's Gelassenheit (translated as Discourse on Thinking).
 

The SA issue is one I've been following since translating Heidegger's Shadow. It seems that in order to become rector he would have needed the support of the SA, because they controlled the student unions, which had some sort of veto power. And it seems he quit the SA when he resigned, a month before the purge of the SA. But all those documents were lost...
 

pensum left this comment and I deleted it by mistake:

An article in Le Monde by Peter Trawny himself, translated from German into French, can be found here