pumped milk and daycare

First time mom so I need some advice.  Going back to work next week so I met with her daycare teacher today and they require that the bottles come in ready to go. They will not pour milk from a sealable container into bottle or do anything considered "preparation" other than heat bottle up. So I have no idea how to send in bottles and how much to put in each one. If I bottle feed her I normally give her 4 oz and then if she still acts hungry, I feed 2 oz at a time until she is full. Sometimes 4 is enough, sometime 6 or 8. But they stick strictly to the 1 hour rule so if I make all 4 oz bottles and she eats 6 oz, they dump the other 2 oz. Same for if I make a 6 oz bottle and she only wants 4. And the other issue is if I give her 6 in one feeding, she spits up a lot more.