What size for heavy bleeders?
I normally tell people not to pay attention to the size suggestions because so many people can switch out between the two sizes no matter if they had children or not and no matter what age they are.
Does your daughter know the approximate height of her cervix? If it’s low, I would suggest a bell shaped cup like Super Jennie, Si-Bell, Lena, LaliCup, Fleur Cup. All of these will allow a low cervix to sit inside of the cup without taking up room.
If she has a medium/high cervix, those cups still might work great but she’ll probably be just fine trying any cup in a large size, as well.
My daughter has not had children yet but she still wears all of the large sized cups comfortably and normally uses a Super Jennie large for the capacity.
So basically, you’re choosing a cup to fit your (daughters) needs and not so much on what the guidelines suggest. The guidelines are great for a first timer that doesn’t know where to begin. However, since we know she’s already comfortable inserting and using a menstrual cup, she’ll be more confident with trying the larger size.