I bought the small first, and found it still rather irritating, so I got the mini. For the record, this cup may be advertised as "barely larger than a thimble" but that's just a turn of phrase, in case anyone is looking at a real thimble and scowling. Though I will believe that it's the smallest cup out there. I now use the mini most of the time, and the small only for when I'm bleeding heavily. (My idea of "bleeding heavily" is probably everyone else's idea of "really light bleeding", I suspect.) I still get slight bladder irritation from time to time, but not much and not to the point of needing to go back to pads.
Both cups were rather tricky to unfold, so I bought a 2mm mini hole punch and added a couple of extra holes. That did the trick. Melunas only have two holes, and they are tiny.
I got a ball stem for both, and it's a great stem, but I ended up cutting it off the small. This means that the small (stemless) and the mini small (ball stem) both end up the same length for me, 45mm total. And if that hasn't convinced you of the lowness of my cervix, I've worked out why I sometimes have trouble getting it to unfold. It's not just because of the holes. It's because I keep pushing it up past my cervix, so that's getting in the way. Once I pull the cup down a bit, it unfolds obediently. I must be practically fisting myself by the time I'm groping my cervix, which is a hell of an achievement for someone who had really nasty vulval pain this time two years ago. I am back to rejoicing over menstrual cup use, and singing their praises to as many people as I can politely manage.
By the way, the cyan is really teal. And a very nice teal it is, too. I got the silver sparkly one for the other cup, and that's reasonably nice, though not as pretty as the teal. But I do like having two different looks for the different cups. The pouches are large, so they both fit in one pouch.