Thanks for the tips. I checked the lawn this morning and the yellow spots are spouting green blades! However, I also noticed a few brown mushroom heads. We did have 2 heavy storms in a row so the grass was probably really moist for the mushroom to grow right?
I will continue manually watering the grass and the third week, let my rainbird do it automatically. Does 20-30mins per zone for 8 zones seem reasonable. Possibly around 5-6AM?
If it gets hot during the afternoon, I will also make it run again in the afternoon for again 30 mins?