Hi, read your Diva Cup review. The sizing is based on age 30/or having had children as those widen ur pelvis slightly, not to do with flow amount. I've used it about 4 months now and there is a learning curve, make sure ur not inserting deep like a tampon, should just rest low in the vaginal canal more like a plug, tilted towards your back than upwards, with that nub just within/inside the opening of vag lips, so it's not poking out ur body on underwear. Some women mistakenly push it up towards the cervix thinking it should cover it or be closer. I grab that nub with my fingertips to tug to remove, when it's lower I grab the ribbed base of the cup and squeeze slightly to break the seal and turn upon removal. If it moves up inside u during the day, I lean forward & bear down like a bowel movement which compresses the area and makes it easier to grasp. These are just my hints, I usually wear a panty liner the first few days in case, and change the cup 3 times my first day, heaviest flow because I find positioning it hard when cramping and bleeding then & do get a bit of spotting even though it's only 1/2 full, but after that it's 12 hours and no leakage . Do call the Diva Cup help line, (866) 444 3482 . They helped me with the sizing and really want all women to get the benefit of the Diva Cup. You've come this far, give them a call and hear what they suggest. Coz it is expensive you're right. Good luck! :-) http://divacup.com/