They don't run large compared to other brands I've used, notably Giro and Specialized, but really shape is more important than "size". In other words it could be "large"in one dimension but tight in another. One thing I will say though is that the Kontact that I have has a really nice adjustable retention system so you should be able to dial it in pretty well.
+1 which Giro did you try? Some of theirs are more round, and some more oval than others, and this can make a pretty big difference in how it feels.