I just stretched my seedlings almost 6 inches. There covered up with new soil, 16 inches away from a 400 mh and doing just fine. OP was correct, get the light as close as you can so you don't end with 6 inch streched seedlings like I did.
definitely bring the lights about 2 inches away from your plant. Once it gets bushier (which it should depending on strain) then you can bring em another inch back. but always try to keep the lights about 2 or 3 inches from the tops of your plants.