I think the taller the less it streches. I have a drip system very small with 6 plants. If I start to bud when they are one foot then they end up three or a little better. I just got a hortilux eye 1000 HPS and they are not streching near as much but will end up close to three. I started with a 400 HPS and one plant grew right into the bulb and burned all the tops off at three feet I ccut the tops back and then got a cheap 1000HPS the plant came back to over four feet and half a pound on it. DRY. Like super cropping. What kind of hydro are you useing?