hps

Two 150 watt hps or one 250 watt? Does it make a difference to the area covered?

imo yes one 250 will cover less than two 150 watt not only because it 50 more watts its two seprate lights u would be amazed at what a 250 watt can do
here is 6 plants under a 250

Thanks! I'm designing my flowering room, I have a Flood and drain table at 120cm by 60cm, long and thin! Any advice as to whether a single 250 or two 150 watts would be preferable? Would a 250 cover each end adequatly?

perhaps adequately, but 2 is always better than one. unless its herpes

i would definatly go with 2 with 6 plants under my one 250 i have to rotate them out for each one gets primary light that way all the buds are the same instead of the secondary light not getting them the light they need does that make sense, with thew 2 hps u will get more primary light than secondary