500g is a little over a pound so that would be way too much to add. For a recent porter that I made I used .25 lbs (115g) so that might be the most you'd want to toss in there.
Keg 1: Tropical something-or-other IIPA
Keg 2: Pigskin Brown
Fermenter 1: Kolsch
Fermenter 2: ESB