Matt,
The scenario you described (classes running into one another on the course) happends anyway when you get beyond 2 or 3 classes on the same course. Sure, we can minimize it with timing (wait for the lead class to be around the gate before sending the 3rd start), but once you get past 3 fleets, it's almost impossible to avoid all issues. While dual weather marks helps, they all need to go through the gate eventually...
Other than holding everyone back to reset the course, do you have a better option?
Mike
Timing becomes exquisite with 4 or more starts. Or - you can go back to the mid-course line, which works really well in this situation (more than 3 starts).