Hi Max,
I have Ltn. Wolfgang Ziese "der Baumiestere Hecht beim Versuchesverband OKL Oranienburg" making the following flights described as "einsatz", all in Arado Ar 234 B-1 WNr. 140153 T9+HH (SM+FM), in October and November 1944:
13.10 14.23 - 16.24 Uhr
18.10 9.07 - 11.08 Uhr
25.10 12.05 - 13.58 Uhr
30.10 10.05 - 12.20 Uhr
4.11 9.56 - 10.55 Uhr
en.wikipedia.org/wiki/DFS_346
The above source has Ziese testing the DFS 346 in Russia and still alive in 1951.
deZeng and Stankey have no date of birth and make the cryptic comment that he died under "mysterious circumstances".
best regards,
Jim Geens