I'm currently using Reef Chili from Bulk Reef Supply (http://www.bulkreefsupply.com/brs-reef-chili-coral-food.html) and found that my hammer and frogspawn retract almost instantly when I feed them. Same with zoas, once the food hits them they retract for a couple of minutes and then come back out.
I've also tried Reef Roids by Polyp Labs, and Coral Frenzy. Of the 3, I like the particle size of the Reef Roids the best. The Coral Chili elicits the strongest feeding response from the corals, but now matter how much I mix it there are always chunks. I think the smallest size of Reef Chili from BRS would be a good place to start since it is only $13....might not be too late to get in on this months group buy at BRS either? http://www.marinecolorado.org/forums/showthread.php?29123-August-BRS-Group-Buy&highlight=bulk+reef
You would be surprised how much hammers can be fed just from the food you feed your fish and copepods that populate your tank. I don't feed my euphyllia anything directly and my frogspawn has grown from a single head the size of a golf ball to the size of a softball in 3 years.