Well, Cousins delivered the Inca shock assembly a while ago but only today I had time to work on the movement. I tried to insert the shock assembly into the mainplate and found out that it does not really fit in the hole 
Replacing the shock assembly does not seem to be the way to go. 
Good things happen also: i found the missing shock spring in my parts tray 😮
I guess it must have been stuck to another part without me noticing. So I might have another try with the original shock system. Trying not to loose the spring 🙄
