in the operation section of the action target from the drop down window you can choose
transpose to scale
then you get another drop down window where you can choose a tuning
My question is can you add other tuning files to this list.
MK
Not a specialist of working with scales in Cubase, but it seems that you can.
First, use the Project > Chord track > Set up Musical Scales… command. This one is available, here, even if there is no chord track in the project. Add and configure the wanted scale :
Once done, the newly created scale should appear in the Transformer/Logical Editor as an added option in the Parameter 2 list when the Transpose to scale option is used as operation in the bottom panel (Event Transform Actions).