Hi Russ,
That was just intended as an example. Watering frequency depends on transpiration mainly, which is influenced by environment, (temperature and humidity, rainfall, barometric pressure, I suppose, and drying forces like sunlight and wind) but also by factors like the size of the container and plant, species, the type of soil used, and for many plants also depends on the seasons when they are most active.
In winter I will be watering as rarely as once every couple of weeks when there is periodic rainfall, to perhaps every day and rarely more than once a day in the heat of summer. That second watering is mainly to cool the plants more so than to provide moisture.
If you are monitoring soil moisture, you will have the most critical factor available, and it probably wouldn't be important *how* the soil got dry that day. It might also be valuable to have a single temperature sensor which could be used to actuate a mist system periodically in the event temperatures become excessive, but then that almost begs for a photosensor so that you would not be misting at night...
I am certainly interested in your system and would be willing to "test and tune." I'm sure that reliability would be a major issue and that might drive some need for redundancy.
I've experimented in the past with various drip loops and soaker hoses as well as "shrubbler" type emitters. I never really trusted anything enough to leave town. But now with the internet and a webcam, who knows
Regards,
Matt