After this miserable failure of trying to fix a perfectly good design, I just thought a bit harder about what could be the cause of the tilt. if it’s not the designer’s fault, maybe it is mine (of course I tend to give credit to this option only after a couple days of bitching and trying to “fix” everything :p)
And maybe I found something…
In my build log, you can see that I had a few issues with the printed YZ plates, that were just a bit too tall and caused binding on the Z leadscrew
This was due to my printer’s Z axis not being calibrated, and it was printing “too tall”
Well… here’s the core in it’s recommanded printing orientation
Let’s say my printer has a tendency to print “too tall”, and exagerate it a bit:
If we turn this around
Well, the model is deformed, and everything but that’s not the point, my printer is not “that badly” calibrated 
The interesting thing though, is that, through the slight angle the core has when printing, the two mounting bracket holes are not horizontal anymore
Could this be an explanation?
I’m not particullary willing to re-print the core just to test that theory 
Any other idea as to why I get this tilt? Or a way to get more adjustment and correct it?