I just tried EZdrummer 3 with Gig Performer and I found that I could only learn the dials below the mixer. I’m not quite sure why there are 100 Params.
However, after a little experimentation, I did find that I could manually associate CC numbers with sliders in the mixer and then by mapping widgets to the appropriate MIDI CC parameters the sliders could be controlled by widgets (and then of course you can leverage GP’s scaling curves etc)
Unfortunately, host automation for those MIDI parameters doesn’t seem to be fully implemented since moving a slider is not triggering host automation so you can’t have Gig Performer learn the MIDI parameter. Consequently, all the mappings need to be set up manually.