Hey - I also saw some other questions/concerns you posted and figured I'd take a second to share my two cents. MycoMadness & White Widow are beneficial bacteria. There are lots of other brands too. Beneficial Bacteria are "beneficial" in that they promote root & soil health. They help process nutrients/fertilizer and make it easier for the plant's roots to absorb. They also eat (?) dead roots that are decomposing. I don't have a real solid understanding exactly how they help, but that's the basic idea I got while talking to the guy at my local hydro shop. Some research on the topic may not be a bad idea. Even if you don't know what they do, you should give them a shot on at least one of your plants so you can see the difference it makes.
You also asked about Humboldt Roots - this stuff is a "root innoculant." Again, I'm no horticulturist, but my understanding of this stuff is that it's basically a fertilizer for your roots. It will promote & stimulate growth of your roots. Your roots are where all the magic comes from. Problems above the soil are often a direct representation of how healthy your roots are. If your plant has slowed/stopped growing your roots/soil might be too saturated with water and, therefore; starving for oxygen. They may have run out of room in the pot. They may be unable to process nutrients due to an imbalance in PH or salinity (lockout/defficiency). They could need water. Plants with the same genetics will grow larger in a 5gal pot than they would in a 2.5gal pot. That's because MORE ROOT = MORE FRUIT. Also if the container isn't deep, but is very wide, your plant will likely end up short and bushy.... if your pot is narrow and much deeper the plant will probably be taller & narrower. The idea here, is that in order to take care of your plant - you have to first start by addressing your root & soil health. I mixed the Humboldt Roots & MycoMadness into gallon jugs of Ph balanced water and wetted the soil with it as I was mixing in my pearlite. It is definitely some fertile stuff!
You also talked about your light schedule & intensity. I would start your seedlings off at 150 watts if that's the lowest your light goes. You would want to use a MH bulb during this stage. If you want to save on electricity you can even use a Flourescent or CFL during these first few days since they really don't require super intense lighting. You could probably switch to 400 watts after a 5-8 days, depending on how healthy it looks. Definitely after you have a couple sets of true leaves (the tear-drop shaped ones that come out 1st don't count). How close you are able to keep the light to the top of your plants is going to be dependent on your setup. Hang a thermometer/hygrometer a few inches under the light & see what the temperature is... keep moving it towards/away from the light until you find where the temperature is no warmer than 80 degrees. This is how close you want it to the top of your plant. For some reference, my air-cooled hood is about 1.25 inches from the tip of my main cola, but my buddy who doesn't air cool his bulb has to stay about 18-22" above his plants. You'll also want to tackle air ventilation and circulation with some fans - if not, the heat will become arch-enemy numero uno muy rapido! I would keep the lights on an 18/6 schedule from the beginning to the end. That is the advice I've read in many, many places. I ran into a problem where my plants were getting taller than I wanted or expected them to, so I reduced the nitrogen and hours of light to try and curb the stretching - It seemed to work well, but could have just been coincidence; who knows? So she started on 18/6 for 45 days, then 14/10 for 16 days, and is now on 12/12 until harvest. I know I could have given it 18 hrs light all the way to the end, but since I'm not in a hurry, I wanted to go with 12/12 and see if it would make the plant hold out longer (and maybe produce more) before coming to her peak ripeness and getting harvested.
I hope you can make sense of my long-winded ramblings. I do want to reiterate the fact that: I am in no way, even remotely close, to an expert gardener. I hesitate to even give advice for the fear that I will mis-guide someone. There are many top-notch farmers on this site, and I would certainly hope they'd chime in & call BullShit on me if I've told you something incorrect though. I wish you the best of luck & can't wait to see your setup & 1st harvest. Peace