Hello Robert,
I crawled the web to gather more information about this heavy Flak unit to obtain photos, details on 88 or 105 mm cannons as you mentionned or report concerning the hits on french Bombers.
I found this page
http://www.ww2.dk/ground/flak/abt/s902.html I don't speak german but I am sure it is this flak unit as you did.
Maybe you or someone has more details on this unit or better links?
Regards
Jerome