It is done!
My new Thing-O-Matic is happily printing it's first calibration objects.
Right next to my trusty old RepMan.
I left a LOT of comments about missing details, misleading photos, unlabeled parts and other such shortcomming on the talk -pages of the assembly instructions-wiki.
I also recorded every step of the mechanical setup on video. Currently I'm low on disk space but with some new HDDs I should be able to make an assembly-video explaining what the instructions omit.