I usually feed a combination of PE mysis and cyclopeze. I first drop in a few shrimp pellets to get the scent/taste of food in the water so the feeder tentcles of the LPS come out, I then soak my food in combination of tank water, selcon and garlic extreme for about 15 minutes...Do a light broadcast feed to distract the fish then target feed my LPS. This will give your LPS time to consume whatever it is you feed so you're fish/inverts are not stealing it away.
I usually feed my LPS when I feed my fish frozen food...which is about every 3 days. My frogspawn doesn't usually except food, but my duncan gobbles it right up. No experience with open brain, but from what I have seen they will definately take food.