Bo's demos are always good.
The "Voices / Voice Spread" mod source is new to Sequential's instruments... its something I've been lobbying for over the past couple years... certainly happy to see it in the Take 5, and hopefully future instruments will get it as well. The great thing about having voices as a mod source, is that it allows you to do custom vintage voice variance modulation, with a fairly straightforward workflow.
Previous instruments have had VCA Spread Panning controls, however that's a hardwired modulation of voice number to amp panning. This source can accomplish that type of amp panning as well, just by routing Voice Spread -> Pan.