Iirc, weren’t lots of women going to send their used pads and tampons to that GOP politician something something monitor schedule to detect abortions…?

I’m post-menopause and post-hysterectomy myself so I didn’t pay complete attention, just sort of cheered them on.

Anyway you could start by doing a study based on recording the real-life experiences of a large pool of women who self-identify as having “normal” periods. To set a baseline at least, by which to judge “heavy” bleeding.

Or a smaller pool who are willing to alternate cup and tampons to better measure capacity. I think pouring from cup to tampon would be inaccurate because pressure from the vaginal wall affects tampon capacity.