For those of you who have used both sizes of the Lunette, how much is a difference is there between the two? Size wise, capacity wise, comfort, etc. I've decided to order one, but I'm concerned about the capacity. I currently use a small Miacup, and have to empty it about every four hours on my heavy days. But I'm afraid that the large size will feel too big inside of me. I'm just not quite sure what size to get.