User blog comment:Mihaelandnate/The chronicles of mihaelandnate's failures with VOCALOID- vibrato edition!/@comment-2020924-20140505010958

Often times it's not only finding the perfect/fitting cycle, but also finding the balance between the cycle and depth, just play with the settings until it sounds right. (*This from my experience with UTAU). Typically having a strong vibrato with high cycle will make it sound awkward and unrealistic, and too small of a cycle will make it sound rather nasty (I'm not sure if VOCALOID uses different words for these things, but the depth is how much the vibrato goes into the surrounding notes? i suppose and the cycle is how close together the waves are)