My first grow (pics) and some questions for my 2nd (400 vs. 600W)

Hey guys.
 
Just finished my first grow, and, while I dealt with a lot of issues (humidity, health problems, took to long to repot, etc.) I learned a lot and think that my next one can be even better, and much more efficient.
 
Here is a pic of the two types I grew. The one on the left is Purple Kush and the right was some Pineapple Haze, or something... not entirely sure.
 
I used a grow tent for my first go around, but am going to renovate my closet and use that this time and I've got a couple questions I'm hoping you guys could help me with.
 
I'm curious what you guys reccomend for a light? And whether I should utilize a 'cool tube' or not.
 
The room is 4.5' wide, 3.5' deep, and I am going to make it between 4-5' high. I was thinking about running a 400W MH and 400HPS for flowering, and doing 6 plants. This sound reasonable? Do you believe there would be a big difference in yield with 6 plants under a 400 or 600W light?
 
The other thing I was wondering is if I should use my reflector hood, get a tube, or just use the plain reflector.
 
During my grow, one set of plants was under a 600W light which was in one of those big, rectangular metal hoods with the glass on the bottom and the bulb inside. Either end has a hookup for tubing / air flow. The other set of plants was under a large 'wing' style reflector, and seemed to do better with everything else the same (temp, humidity, nutrients, etc.).
 
I read online that the glass panes can remove some spectrums of light and is detrimental. It also projected a narrower light field, and the ones under consistently were worse off. Do the small tubes do the same? I know keeping the temps down would be a breeze with this, but I would rather the light be used fully. What do you guys reccomend?
 
 
The room could hold 8 plants, at which point I would probably go to the 600W, I just worry about heating issues.
 
Secrecy isn't an issue, and I will have a pretty solid ventilation system, with a cool / fresh air in, one pulling hot air from around the bulb, and another plan within the room when / if needed.
 
Is 400W decent for 6 plants, or do you think I I should go with a 600W?
 
I will be growing in soil, as I did last time, and have a much better understanding of utilizing PPM of soil and feed now, so I am expecting to have some fun with this go around.
 
Cheers guys!!