I think the cut off for lunch was 2:30? That might differ from year to year though. There isn't a mass start however which is quite nice, though there will still be plenty of cyclists starting at the same time. I am just not all that fast which is why I like to start early, take my time to enjoy the ride and still arrive at lunch before the food runs out

I agree those first few miles in particular can be interesting, especially with those who may not ride often or haven't learned how to ride in groups. That seems to usually be sorted out by or before the first SAG stop - at least that has been my experience.