After I already gave a preview of the milling platform,
I was not able to do the first actual tests.
I was able to mill the top side of a Makerbot Endstop v1.2 nearly instantly.
I used my Repman milling toolhead, the Repman to T-o-M toolhead adapter, the new PCB-holder platform and the quickchange-modiciation to remove the automated build platform.
A video with all the details is comming soon.
(I already made the footage but need to organize it, make voiceovers,...)