I would think the best way to set up a keyboard would be with all the global out settings flat, and use a good set of headphones to set up the internal EQ settings etc. Then when you go out to a gig (Or use the on-board speakers) you set the global out settings to match the sound system and environment safe in the knowledge that all the internal settings are correct. (Internal and External settings are totally independent, or at least they should be)

Bill