The best stimulus for increasing lactation are feeding at regular intervals,a good diet by you and a relaxed state of mind. If you feel your lactation is less,what you need to do is give your feeds at 2 hour gaps followed IMMEDIATELY by top feed,if your milk is less,she'll take good amount of top feed. All formulae are more or less the same. Maintain hygiene strictly. As far as possible,avoid top feeds. Good luck.