My DD is five weeks old and while I'm not planning to express or bottle feed expressed breast milk for another three weeks, I would like to start saving some of the copious amounts of milk I'm currently leaking. I've bought the collection shell things you put in your bra and it says to only collect the from one breast when you're feeding from the other. I was planning to collect the proceeds in a single bottle over the course of a day or two and then freeze. Is it ok to top up and mix milk from breasts like this? What happens about fore and hind etc? Any thoughts/tips/advice?