reflecting light is not gonna be enough to even do anything for the plant , direct light is what the plant needs. When i went to do my first grow the local grow shop advised me that foil walls in the grow room r over rated and do nothing . so i went with the white walls and he was right , the walls have nothing to do with growing . its all about the direct light u r giving to the plant .
Mylar is the best White walls are good Alu foil is the last resort. Definitely have one of the options surrounding your plants for max illumination.
Foil is bad since it creases and will focus light much like a magnifying glass and can cause burns on your plant flat white or Mylar is the way to go Keep calm and grow on Kush