In the past using MainStage, there are times when I may change hardware and/or a MIDI input port for a given keyboard for my concerts. MainStage has the layout designer feature where you design the keyboards which will have plugins assigned to them. So if you have two keyboards, then each MainStage page will map different sounds to each keyboard. If you change the keyboard or the MIDI Input device, then it is rather easy to change the MIDI input for each of the two keyboards and create a new .concert that maps to the new MIDI Input interface(s). You don’t have to change each concert patch.
Using Gig Performer with two keyboards, I can see setting up each rackspace for a given song (or set of songs) and each variation to have two MIDI Input Plugins for each of the two keyboards which identifies the MIDI Input Interface. And using the example referenced above of two keyboards, if there comes a time in the future where the MIDI Input needs to change due to hardware replacements, then each rackspace ane each variation in all of my .gig files would need to change. Perhaps there is a way to implement a MIDI Input Mapping feature for the .GIG file or for the global application. This allows the .gig files to reference an abstracted MIDI Input, while you can then map the physical MIDI Input connector to the abstracted MIDI Input that is used by the .gig files.
This would save time if there is a need to change keyboards for a given performance.