Pound together chiles, lemon grass, shallots, galangal, candlenuts and shrimp paste or grind in food processor or blender, adding 1.5 tablespoons oil. Stir in turmeric and coriander. Heat remaining oil in large saucepan. Add ground ingredients and fry gently, stirring frequently, 4-5 minutes. Add dried shrimp and fry 2 minutes. Remove thick coconut milk from top of unshaken can with ladle. Combine remaining milks. There should be 3 cups thinner coconut milk. Add thin coconut milk and reserved shrimp stock to fried mixture and bring to boil, stirring constantly. Add fish balls and simmer 5 minutes. Add thick coconut milk and salt and simmer until gravy thickens.