A Couple Questions about a Closet Grow

Hey, I don't know too much about marijuana growing some of gardening but my boyfriend is doing a closet grow and I have some pretty simple questions. First off, we're using the Canna cocoa system; soil and all the nutes [a+b, rhyzizome, boost, and whatever else] The tent is 2x4x6. Firt question, for vegging how high should the light be? it is a hps 400watt.
We were planning on following the regular Canna schedule, but I've read up and was wondering if we should use less of the nutrients while vegging then add up? How detrimental is it to the plants? How often to water and when to add nutes?

Also, we are growing AFWRECK and BLACKBERRYxBUBBAKUSH.
I heard depending on the strain, we may need to water less or more.

Any help would be great!
Alson the chart there are columns EC+3 and PPM. What do these mean?

the first question should not be about the height of the light, it should be how close to the plants. and with a 400 watter it should be as close as possible without burning the plants. just stick your hand under the light. if it is too hot for your hand, it is too hot for the plants. the exact distance will vary depending if it is air cooled or not.

as far as the nutes go, it is good to start at 1/4 dose and work your way up to full dose. you can use nutes every time, but most people will do a cycle: nutes, water, water. or nutes water nutes water. just find what makes the plants look happiest.

and i grow afwreck too (afgooey x trainwreck), but i call it rainwreck. in any case, she gets a little leggy and does like more water than some of my other strains.

good luck!