GET THE FORECAST
Talk to the navigator or whoever is most clued up about the weather forecast for the race, so you know what conditions to expect at which point in the race. That way you can make sure the headsails are stacked in the best order for what you’re expecting to use first.
Make sure you can easily identify the sails. These days every single sail often comes in a similar bag; it’s the same shape, the same length, especially on IRC boats when you’ve got five jibs, five kites, etc. So have all the bags and sails properly marked for easy identification.
If you’ve looked at the forecast and you know the first day there’s no wind, then you can probably put the heavy jib on the bottom. But if you know the first day is going to be 30 knots, then put the light wind jib on the bottom.