Diva Cups and Moon Cups are basically menstrual cups, just different companies/brands. They have different sizes, but generally they are made to be fitted comfortably inside the ****** and allow no leakage. I've never used them, only researched them. My main feeling on it was that it just wasn't all that safe to plug up your ******. I think a lot of things need to come out, so I'm going with the cloth pads - I already use the disposable ones, I prefer those over tampons. I'm working on making patterns of my own - all you really need are a sewing machine, fleece, cotton, a pattern, and threads.
As for just purchasing them, there are people that make patterns of their own, too. Here's just one out of many:
Ama'z Padz Online Shop
As for hysterectomy, I'd be very careful although a lot of people have been fine with it. My mother had one and she wasn't very careful with hers. Years later down the road, she had a little bit of a falling out inside and it was incredibly painful. She had to have a surgery. There were also a lot of other variables, but I'm not sure what else caused that problem for her. She is getting close to her 60s. So definitely give your body a lot of time to heal - treat it like you'd treat any surgeries or wound. Fluids, rest, gentle diet.
For cramps, I just stick with a heated pad on my stomach, some massage, and aspirins. Hot tea of all kinds generally helps. A good hot bath or shower also helps me. I've never really heard of mint tea being specifically special for cramps. A google search brought these:
Treating Menstrual Pain with Chamomile and Mint Tea. - Natural Treatments and Remedies - Mamaherb
Dr. Tea's Tea Garden & Herbal Emporium - Herbal Tonics and Remedies, Gourmet Teas Since 1988
"Peppermint's pain-relieving effects on headaches have been known for many years." (I guess it's not much of a stretch that mint with pain-relieving effects can help with cramps, right?)