Great thread.
This may be of interest. In the confusing parlance of Jukers aircraft it's either a J4 (Junkers) or J1 (IAS).
Starboard wing root of the centre section, upper wing. Hopefully the angle helps. Easiest to remember that the inner, folded, 'C' channel and outer round tubes provide 3 dimensional triangulation. Great space frame design.
Regards,
John