Hi!
As it was to be expected, I ran into troubles in my first restoration (see introduction post). Mainspring was broken, and I don’t seem to be able to find it. These are the measurements:
Barrel inside: 22.0 mm
Mainspring thickness: 0.2mm
Mainspring heigth: 2.25mm
Mainspring length (putting the pieces together): 790 mm
The movement looks to me like a Roskopf Patent (1a??), and the mainspring seems to have and additional insert where it attaches to. (See attached pictures).