How close should MH light be for seedlings?

I've read that during veg, a 250W MH light can be about ten inches from the tops of the plants, but that for seedlings, MH lights shouldn't be used at all unless they are kept 3-4 feet away. Won't this cause stretching?

My Lumatek digital ballast will let me dim the light to 100, 150, or 175 watts. Could I just dim the light for seedlings without having to move the light so far away?

I should mention my light is in a cool tube...

i have the same setup but mine is 400 hps..i dimmed mine down to 250 and had my cooltube 18".this caused stretching so i lowered it to 12 inches.seemed to work out

I use 400's and keep them about 10" to 12" away, you should be good as long as there is no heat.