I tend to water dechlorinated tap that has been ph'ed down to 6.3 and between 1/2 gallon and 3/4 gallon every time I water. My soil was moist, but the plants were good and healthy when i transplanted from solo cups, zero shock and for the next 7 weeks booming and stacking up.
I also water my living soil that way.
Over-watering, and being too caring will result in disaster
Think of soil moisture on a scale of 1-10. 1 being bone dry and 10 being muddy wet. We want to operate in the 3-7 range all day long, day in and day out.