Re: Coal Question
Generally I find that if my hands are slightly damp from rinsing after putting the tobacco in, I get better grip/traction on the foil and can get it pretty tight. Just be careful though because at that point you can rip it along the edges.
Like Fresh said above, make sure that there's a good amount of space between the foil and the tobacco so it doesn't burn onto it. When poking holes, take into consideration the type of tobacco you're using because some are more resistant to heat than others. The more holes you put, the less heat gets trapped inside, so it's trying to find the right balance of holes and coals to get a good smoke.
The general idea I implement for using my windcover is I'll start off with it until my bowl is nice and warm, getting good smoke, then I'll take it off. If the temperature drops too low and the smoke gets bad, I'll take a coal off and put the windcover back on. While hookah is a relaxing pastime, sometimes tending to the coals will keep you on your toes. I with you luck in getting the outcome you're looking for.