Question about menstrual cups

Je

So I have a pretty heavy flow and have been wanting to try a menstrual cup for a while now. Usually there are two sizes (one for people who have had kids and one for people who haven’t) and I was wondering if the bigger size would be better for someone who has heavy periods. I haven’t had kids but I don’t want to leak because I would have to use the smaller size. Hope this made sense:)