Well the light came today and the instructions don't give you much leeway on where to put the light. The light has to be put 12" down from the top and 12" from a vertical stay. 12" down is only a few inches below the water line. I would think it should be deeper.

My next question is should I wait until the pool is almost filled before I cut the liner? I'm guessing it will stretch a little and if I cut the hole ahead of time the liner may wrinkle.