Let your intuition be your guide. Like you noticed with each practice your intuition guides you into form. It does the same for which direction to face and where is the best place for you to practice qigong.
One of the reasons you don't want the sun directly in front of you when you do something like qigong is simply because even with your eyes closed the light can be a bother and opening your eyes afterwards or even during the exercises cause discomfort.
Alex
