i have found that providing plenty of places to hide (with plants, real or fake), decreases the amount of aggression in the tank.
the only time i really found my gouramis chasing each other was mealtime...so i started dropping food at opposite sides of the tank.
i think its good to start with a pair. if you start to notice aggression from the male to the female, you could always add another female.
if you wanted to mix dwarf gouramis with larger gouramis, i would go with sunset or honey dwarf gouramis with pearl gouramis. the pearl gouramis, from what ive read, seem to have a milder temperment for a full sized gourami. even the female pearls have beautiful coloring.
hope this advice helps...
jeans