Girls with CAH and cups?

Hi! I'm Kait, and I'm a newbie who's exploring the possibility of using cups while traveling later this year. Nice to meet you!

Before I choose a brand I wanted to seek your advice. I'm in an unusual position because I have a genetic condition called nonclassical congenital adrenal hyperplasia. Basically, what that means is, I have a mutation that causes my adrenals to produce a little too much androgen, and among other things, it slightly effected the growth of my lady bits. (It could be a lot worse because women with the classical form sometimes don't have a vagina at all!) In my case, things look basically normal, but my vaginal opening is shifted a tiny bit forward from where it should be, and it is also somewhat narrowed. The rest of my vagina seems normal. For example, I am okay with inserting tampons with an applicator, but if they are the type that open around rather than vertically (I'm thinking Playtex) they almost always get stuck at the entrance, even when soaked through, and are very difficult to remove even when I am completely numb from applying ambesol to the whole area. Tampax are okay because they expand vertically. Does anyone else have this issue or know someone who does?

Aside from all that I am really interested in using a cup if it will work for me. Because of my CAH my cycles are pretty irregular so I often end up wasting pads on days I think I "might" get it, only to finally get my period 1 or 2 weeks later.

Just for your information I will include some other stats about myself, and if you think it's even possible for me to use a cup, maybe you could recommend one for me!

Age: 26
Virgin
No kids, obviously (pregnancy probably won't happen for me and CAH women almost always need c-sections anyway, so I probably wouldn't need to change cup sizes if I did have a baby)
Average height and build
Depth of vagina: Not sure what it is during my period because I'm a few days off from it, but today about 7-8 cm? When I do insert tampons I find that I usually can't get the plunger pushed all the way into the applicator, the plunger just "stops" about 1/2 to 1 inch short of it, but I don't feel like the tampon is too low or uncomfortable inside me. Does that mean I'm short? I've heard short vaginas can be an issue with CAH girls. I don't really know what the scale of "short" or "long" vaginas is either...
Flow: On the light side, but my periods tend to be long, due to thyroid issues the CAH can cause. On my heaviest day I might get through a super tampax in 5 hours or so, but they might be less absorbent than playtex or others.
Anything else: I'm not sure if this matters, but I really don't get cramps or PMS at all, probably because we produce so little progesterone that would normally set off those symptoms. (Definitely a perk!) I would want to stay away from any cups known to cause cramps though. I really can't handle cramps on the very rare occasion that I actually feel them!

I was looking at some of the charts I could find online and it looked like the best options for me could be the small Meluna or maybe the small Lunette...I definitely want something soft and the narrowest size available but wasn't sure what length I would need or what would fit my capacity needs.

Thanks for all your help!!