My girl is about 2 months and she drinks about 120ml-140ml per feed and takes 6-7 feeds a day. I read before you can estimate 1kg=150ml. So if your baby is 5kg, baby will take about 750ml a day.
Not sure what you mean when you say it's a waste to use milk bags. You mean waste EBM or waste money buying milk bags? When I return to work, I plan to use milk bags to store cause can thaw in fridge and still keep for 24hrs. dont't have space in fridge for so many bottles.
Yes, can definitely transfer one bottle to the other to feed. But take note that you need to follow the date of the older bottle.