well i have 2 1000 watt hps in a 60 inch cool tube.. in a 10 x 8 x 7tall room.. im thinking about adding like 5-10 2 bulb 4 ft flourecent tubes.. so anywere from 10-20 more tubes.. just because i have plants that are almost 5 feet tall.. so i trained them to be bushy. but id like to get a little more out of the side nugs instead of a ton of popcorn buds.. do u think 10-20 bulbs will have a big affect on the yield or am i wasting my time.. and energy