HI - I am expressing breastmilk 10 - 12 times a day. Am now trying to work out about storage etc... can anyone tell me about breastmilk beags - do they fit to the pumps.... Also has anyone ever use the different nipple size breast shields for the medela pumps? I've got the ones the hospital provided but am not sure how you measure and if it makes and difference to comfort or quantity of milk? Thanks for anyone who replies...