Boy, you seem to have a lot of questions for everyone? I guess your just a little pumped, slow down you have time. Did you already buy the light because I got my 600 watt digital mh/hps switchable with two bulbs and a hood for $212.00 delivered to my door. They are not the best bulbs but you could upgrade after your first harvest.
I know your concerned with yield, The gold standard is 1 gram for each watt, you will probably not attain this your first few grows. More is possible but less is the rule.
So lets go with 200 grams (good Karma) if you were to grow your 5 plants to 24 inches in veg. The 7 gallon container are bigger than you need indoors.
I wish you luck with your grow and you should study a couple 600 watt grow journals while you wait for your gear. I said study not question everything OK?
Good luck bro.