OK, let me start by saying, that absolutely NO light leaks is the BEST way to go especially since you are in complete control of the circumstances of your grow area..... That being said, A pinpoint of light or a small glow from an unsealed corner in the room is not all that bad. In the wild there are these small sources of light known as stars, and one large source of reflected light, the Moon. The light pollution that hurts the most is when you go into your grow room during dark periods and turn on a light and sit there to look at your girls. Any high burst of light on your plants foilage wil start up the plants processes for the day cycle and then the lights go out again..... that is where the stress comes from.
Also as far as hermies are concerned, some strains will just be more prone than others to turn. :confused2:
Anyway, Good Luck.