Even tho in this video, the audio speaks in German, there is much interesting video info available. Selecting proper aged wood (holz) and the fine details of adjusting a pipe's speech characteristics for instance. Gives even greater appreciation of all the features present with Hauptwerk (including voicing in the Advanced Edition). Never realized an organ voicer sometimes needs to stand on top of well braced wooden pipes to do his thing. No sky hooks or cranes in a pipe chamber.
Further there is examples of mechanical musical instruments. Just, all in all organ wise, very interesting.
https://www.youtube.com/watch?v=JTRmOPLrr6oRgds,
Ed