Here goes, keep your temps around 75 f and your nodes will be tight, if you get to warm they will stretch. Be careful with your night time cold, during your veg, they dont care to have it so cold that is more for trichome production late in the flowering stage. You should feed them at about 1/15th the recomended feeding schedule when you first move, about a week after that you can bump it up. I would not be topping that plant as it would induce horizontal growth and I dont think you will have much room for that. Right now I have 4 plants that individually would fill that space (not a church). If you are finding that light is not penetrating down to where you would like, with enough are movement you can drop right in a 35w cfl to get the hard to reach areas. I am not sure how far down your lights hang but, you should be 12" or a little more at harvest time depending on the strain. Your plants are going to stretch when you move to the bloom phase approximtely 6-8 inches. So when you switch, you should be 20 inches away from your light at its highest elevation. If you start noticing some bleaching of the top leaves get the light away or gently bend the cola over unless you are in the last couple days of the bloom then bleaching okay. If you are growin in soil, I would be looking into mycorizae, seriously check it out. Also, to stop wasting money on seeds, if the dome is wet, you dont need to water it. I have seen these things hatch on my counter top just sitting there. Also, take the dome off once a day for fresh air. This helps keep away, molds and rotting. Dont plant deep. I put mine on the soil and pushed it down flush, then a very light sprinkle of dirt over it, and I mean very light. Hope this helps.
If it cant be mylar then it must be white.