I don’t think the big one is programmable like that.
I have the Compact and it is COMPLETELY programmable.
I use it as a Generic Remote for CCs, Edit commands, Control Room Volume, Click on/off/volume, Tempo, etc.
Works like a charm.
Haven’t programmed “Selected Channel Fader” for it, thought, since I have 3 MCUs.
Just need to make sure it’s available as a Generic Remote Command.