Question about vegging

I usually veg with a couple shop lights and cfls but my seedlings dont seem to like it very much at the moment. I switched to a hortilux 600wt super hps today and its set on 75% power and is about three feet above the seedlings. My questions are:

Do you think they will be as vigorous with this light as they would be the tubes? I know ive got more lumens with the 600 and its suppose to have a blue spectrum in it.

Is three feet too far away from the seedlings?

Three feet is good for the first few days the move it closer. I would go down to 2 feet and see how it goes.

I was also worried about the light being too strong for newborn seedlings but, in the outdoors the sun is much more powerfull than any hps and I have started many seeds in the outdoor sunlight so I guess it really wouldnt make a difference.

id just buy a cheap T5, my plants veg like crazy and they are cheap to buy and cheap to run. What you are spending in engergy for the HPS ull make up in one month.