Wrong info you got there. When I was asked which if the 3 courses in the SIs we would prefer, I said we didn't prefer triangle or "gold cup" (Olympic) Olympic course *if* it was going to be a 45-90-45 shape like they usually set up for the dinghies. I said if they did want to send us on a triangle course, to set the reaching mark high, like 90 degrees. Never said anything about wind speed. Turns out they never used those courses all weekend, anyway, so they could have placed itthe reaching mark correctly for cats without bothering the dinghies.
When I did RC in the past for this type of mixed regatta, we wrote SIs to have completley different reaching marks for the dinghies vs cats, (e.g. yellow tetrahedrons vs orange balls).