Continuing the discussion from Simpler Scheduling for Spring:
A 30 minute delay should be enough, and your runtimes definitely look perfect for the conditions (~10 minutes of watering, 5 cycles). The only other option I can think of is if you create different schedules that stagger the zones even more, but this would have you running for quite some time.
If you use a fixed schedule with more than 3 zones you will be guaranteed to have enough zones running (flex may not run all zones on a given day) to get a longer soak time. Our new scheduling coming out in our 2.5 release will allow you to use flex concepts with a fixed schedule that will run all your zones on the same day.
For next year I want to make the soak time adjustable.
Hope this helps.