Sorry--I should have been more explicit... We're using 65% shadecloth for our GH top, 72% for the west wall. The east wall is bare of cover. In the summer at our latitude, any direct sun between 9:30 AM and 6PM for our oncids is too much. And definitely introduce them to it gradually, otherwise you'll induce burn. On the other end of things, if they're not getting enough light, their leaves will be floppy, droopy, and darker green. So you're trying for the midrange between those extremes.