I'm going to agree "top hat" is a challenge. Just for the fun of it, when I was finished doing my pattern in profile on Monday, I did bow tie, inverted triangles, top hat and spot landing. Inverted triangles I do every flight, as I saw videos of others doing them to untwist lines years ago. Bow tie isn't that hard. Spot landing is convenient in practice.
The hard part of top hat is the last corner, which comes up pretty quick. You're diving at the ground at speed. Seems faster than a square, perhaps due to a square killing off more speed.
Peter