how far down should i put the plants in the 11-plant system?
The water level should be about 1 to two inches below the top of the growing media. That will keep the main root ball moist, and the stem of the plant dry.
what interval should the timer be set for water to flow and the light?
You just need to keep the roots moist. How fast it drys out will depend on a lot of things like the type of growing media, the air temperature, how much growing media there is, how big the plants are etc.. But depending on your timer settings a good starting point is probably a 15 or 30 on/off. As for the
lights a lot depends on the plants your growing and the type of lights your using. But typically 18 on and 6 off is typical.
how much epson salt and calcium should be put in the water? (per gallon?)
That depends on the recipe/
nutrients your using.