Your buds will be a bit fluffier than HPS but still good. Start about 26 to 28 inches with the light from the canopy. When the plants get within about 20 inches keep moving the light up to maintain that distance. Keep it cool, the air moving and all should be groovy man!!!!
I'm sure you can get good yield off the Halide but they might be fluffy instead of hard. I think if you bought a couple of 2700k cfl lights that were warm white they would do just fine and dandy.
one teaspoon full of molasses per gallon will help the nutrient uptake and sugars. plus i hear it adds weight. as far as flowering, you could be alright for bout two weeks of just straight water. but i would get some bloom organics quick. something high in phosporus. a little potassium. teeny bit of nitrogen. i like organics and biobizz is nice but alaska morbloom is good and ff bloom is good too. also get a super high mega bloom fert. too. really high in phosporus. like 5 55 15 or something to get maximum yeild. but i found the biobizz bloom does just great.