Yeah Ventilation is my next concernwell it depends on how much work/money/time u want to put into this.
but heres my ideas on what u gave
its 12 ft long so the space really isnt your problem, but i doubt your light is 12ft long so if its centered and high enough you can probably fit about 8 ideally and max amount of smaller plants.
or less bigger ones. but a 600w light depending on what kind is going to get HOT!
ventilation would be MY first concern.
anyways keep us posted bro
what kind of light do you have?
cool sounds safe enough. any suggestions on a good strain?600 watts will give 4 plants decent light through full grow.