The NARA microfilms of Luftwaffe documents are simply microfilms of the records currently archived at BA-MA in Freiburg, with the exception of the old T-1033 Luftgau enemy aircraft investigatory collection. In sum, if it's not at BA-MA, it's not at NARA WashDC. As already mentioned, very little of the Luftwaffe's records survived the war, which you can read about in this link:
http://www.lwag.org/reference/fla001.pdf .
There are no other records of KG 26. Presumably, Rudi Schmidt had a collection of unofficial postwar veteran's memoirs, preserved letters home from Geschwader personnel and a collection of photocopied Flugbücher to use as resources when he wrote the KG 26 book nearly 20 years ago, but Rudi died in February 2000 so you cannot contact him.
While we appreciate your persistence, Mr. Norton, I can assure you that we have given you our best advice and your further pursuit of KG 26 documentation is illusory.