I'm going to be hosting the room for today, and I have a solution that I think is going to work for the race start, without requiring a caution or a red flag.
Madrid can't have a rolling start, only a grid start. So, we will set the room to 51 laps, and have 1 pace lap. Everyone needs to carefully get moving at the beginning, and roll around on the first lap at a 45-mph pace speed. The race will have a SINGLE FILE start, not a 2-wide start. I think a 2-wide start is begging for a disaster, and makes the first turn 25x more likely to end up in a parking lot. The race starts when I type "GO" in the chat box. I'll also call it out over the voice chat. I will attempt to time this exactly as the leader crosses the start/finish line to start lap 2.
The room will open in about 45 minutes.