8 foot ceilings is going to be very tight unless you put the Gavitas in the ceiling. I've seen a few guys who have cut out holes in the ceiling and recessed them into the cut out but it's a lot of work. The recommended spacing for 1000W DE gavita is about 3 feet from the top of the canopy and you're going to lose a couple of feet from the ceiling to the bottom of the gavita light. That only gives you about 3 feet to work with which isn't a lot.