IMO if you have a fan running, it will cause most mylar films to 'flutter', resulting in less hot spots.white is the best for any kind of plants. if mylar kinks or gets creased it can burn you plants from making a light reflection on one part of the plant. I recommend White or Getting Bubble foil from home depot because that cant crease easily.
I use anti-fugal primer with matte super-white paint,works well!!white paint
YES!!! White paint , simple , cheap, effective!!!DO NOT USE ''TIN FOIL'', WILL CREAT HOT SPOTS, mylar or white paint is best
Yep..........Flat white.