Hydroponice what is better to grow with for your first time coco or clay pebbles?

im goin to have a wilma system the 4 big pot one im thinkin clay pebbels but bein told coco for fist time im getin a grow tent 120x120x200 wot lights do you think i should uers and all other tips will be helpfull thks swalsh84@ymail.com