after years of growing, I tell all people starting out the same thing...
Do it right, or don't bother doing it...
In the end, you WILL end up doing it right... and if u start off trying to do it budget, and ghetto-rig fashion.... you will end up with a lot of spare parts in the end... and a lot of wasted money... (Ask my wing reflectors, booster fans, and zippers)
Go panda film, mylar, or just some flat white paint... foil will make burn spots, reflects too much heat with the light...