i have 6 plants around each light right now...in a month it'll be 12. so you should def have enough room. when you go vertical you also don't have to worry about height restrictions. one time, i had a 4.f foot basement that was like 30 long feet by 50 feet wide by 4.5 feet high. i hung down my bulbs vertical and all the plant were around 4.5 feet high when they were done, and i pulled some serious weight off those things.
another advantage i have noticed using this method. less heat, it seems like the hoods radiate heat. a better yield for sure. i agree that i am def. using the light more beneficially now. the room just seems so much brighter.
this is my preferred method of growing, but for some reason i went with hoods for this grow because i wanted to give scroging a try. that went out the window though now, and i am planning on pulling down 1.5 from each light for sure now. than another 1.5 from the plants i am going to add. *crosses fingers*