i also use Dr. Brown's bottle and i changed the nipple to level 2 'cause DS was getting bored 'cause the milk formula wasn't coming fast enough, and then i changed to level 3 'cause of the same thing, so i guess it depends on how you see your LO, but you coudl try to change the nipple for like 3 days, if on the third day your LO still spits too much milk then go back to the slower level. hope this helps.