Violet Cress - Marks down the racers who are the most likely to take places 1 and 2.
Colchicum - Picks out racers who will not be first.
Nazuna - At least two out of the three racers she marks will be in the top 3.
RESULTS:x50, x30, <the rest>
The event page is gone, so I can't say what was the exact order.
Anywho, I find the swanboat races fun because they have a logic puzzle element to them and I hope there would be more events with elements like this.