How to preset i.e. the midi volume of a global layer/ instrument for an individual and specific song. Is this possible at all?
Yes, you could create a Layer track and send a MIDI controller to a virtual MIDI Port that sends to an Global Layer Volume Action receiving that controller on the same Virtual Midi Port. You would need to start Transport to have the MIDI beeing sent until we have finished implementing chase events, then it would send it as soon as the Song is selected.
However it seems like a bit of a weird way to use a global resource to acheive a specific task…in that case it might be better to create that specific Layer for a specific Song/Part.
Note that you can also share the Instrument of Layers, so if you select an already existing instance of a plugin of a different Layer, the MIDI and other controls of the Layer are still individiually set for each Part Layer, so no resources are wasted.
Finally, you can copy/paste/load/save and duplicate Layers, and even entire Parts.