You know that re-potting now will get you off the hook for a dripper system?
Re-pot into 3 gallon pails, give a good soak, and they will be fine for the weekend.

NO epsom salts in the soil!!! nonononono!

Watering- when the pot feels light. Let the soil dry out fairly well between waterings. There's no number; it depends on temps, plant size, lightness of soil, intensity of light, and n other factors.