I’m all for DCA spill/roll out, BUT I think this way isn’t a good way. Holding down to spill means you have to use one hand for holding down AND can only move faders will that is happening, because pressing SELECT on a channel would shift the function of the CH TO ALL MIX button. I’d say a user key and also a button onscreen when a DCA is selected for DCA spill on/off and if on then selecting a DCA will spill the channels.