Trial and error.
I dont plan on having the roots become actually wet, ever, as thats not the point of the system, I could just DWC or at least low pressure / faux aeroponics then.
So where I am heading too, but maybe until I get there the nozzles will be different, maybe there'll be a pressure reservoir and a solenoid valve ... 1 second or less mist time every few minutes. A simple delay timer with a NE555 could help shortening the minimum 1 minute of the timer to 1s. Also if I go there already I can simply hack up the whole timer myself so it does exactly what I want, the timer I am using is actually for more advanced purposes (day, time ... and so on) but doesnt offer the resolution needet.