At 5 weeks my bf baby would do between 90 and 120mls per feed. But we only did one bottle a day, so hard to judge if that would be the same for every feed. I think if you had 700 - 800ml ready, plus a bit of back up in the freezer you'd be fine. I've got a day at work coming up in November and I'm trying to build up a bit of a freezer stash.
If you multiple their weight by 150/200 and divide that between feeds (say 8 feeds in 24hrs) then that's a rough idea of how much per feed they should have. For mine he's now 4.6kg, so 4.6x200/8=115mls per feed xx