This last month I was able to use my new Yukki. The material of the cup is much more flexible. I especially notice this with the lip and at the base. So far I have none of the irritation I did with the Lunette. I have still had the overflows, though they have been fewer. I think I'm just going to have to have back up on during those heavy times.
So, my initial impression is that I'm liking the Yukki a bit better than the Lunette. I haven't had to trim the stem at all because it is so soft and flexible. I ordered it on ebay and it was shipped from Czeck and took quite a while to arrive, but price and condition were both good. Hope this review helps someone.