8x8 room floor plan ?

so i just finished my 8x8 grow room in the basement i have a few questions. to start i am gonna be running 4 slim 600h by optic led for maximum light coverage. i will be growing in coco. my first question is that the floor is concrete and i am trying to figure out should i build something to get them up off the floor and if so how high should i build them off the floor the ceiling height is around 7.5 ft. my next question is how many plants can i stuff in there for maximum production. ill be using photo plants. not sure what i want to use for pot size either as i usually grow autos in 3 gallon im not new to growing at all i crank out really high quality product just a new setup on a larger scale than i usually do so any ideas and help is appreciated.