Okay, everything is understood now, Mathias.
All I can add is that Frank Olynyk did his research at AFHRA. Researchers of World War II AAF records try to avoid NARA because it is so difficult to find things there due to poor cataloguing and storage.
I think your methodology of trying to penetrate the 358th Fighter Group veterans' association is the correct one. Almost certainly they had an active postwar veterans' association with a unit historian, a newsletter and annual meetings. But the veterans' association was probably dissolved 5, 10 or 15 years ago when the veterans began dying in ever larger numbers. More often than not, these WWII Groups sent copies of their newsletters to museums and repositories such as the 8th Air Force Museum in Savannah, Georgia, the 9th Air Force Museum, AFHRA at Maxwell AFB, etc. The last (most recent) newsletters might identify the 358th FG unit historian. The 9th Air Force has a museum and library (
http://www.armyaircorpsmuseum.org/ww..._air_force.cfm ).
Go luck with your research!
Larry