My DS feeds 5 times a day (including 1 EMB of 6oz), is 19 wks, weighs 14.7lb. I'm going on a course at a weekend and so will need EBM for the 3 morning/afternoon feeds each day. So 6 feeds in total. How much should I leave for him? Does it work the same way as formula fed babies - i.e. 2.5 times their weight in oz? Or is it different for breastfed babies? Thanks.