okay, i am at a loss which light you like, but it dosent matter, its your decision, Do not change your soil, while miracle gro isnt the best, you'll shock the plants if you change it. It will work, thats what I am using right now. You can however change your nutes, I like organic, or as close to organic as I can get. I like Foxfarm, so do most people around here. The above mentioned site has a 3-pack which covers you from beginning to end for about $38.00
Probaly even have leftovers too.
I'd loose the foil, a flat white paint would be better. Foil will have hot spots. If you insist on using foil, put it up backwards, and never get a crease in it.