Hi, Doug...
With reference to your posting, I would agree about the likelihood of the Gruppe badges being as you state.
The Staff flights for Geschwader and Gruppe I am less well acquainted with myself, but I can say that early on in the war - October 1939 - an He111H-2 coded 1H+JA from Stabskette/KG26, was brought down near Edinburgh and as can be seen from the attached, the unit emblem is clearly a light-coloured (white?) shield with dark, presumably black, detail. I hope so, as I don't want to have to rework my model of this aircraft a second time...
Thumbnails courtesy of
www.flightglobal.com (from the 'Flight' publication of 02.11.1939)
Regards,
Paul