Without alot more info on your desired situation, I really can't answer your question.
Moderation is ALWAYS best, you can always go up later if not enough the first time, but it is really hard to overcome structural damage if caused by overstimulation.
Give us some info on the type of cow, breed, age etc, meybe I can be more helpfull.
One cow may work really well at a small dose where the next one will not -- dozens of different things come into play!
Terry