Check your ph levels - since you are having a "claw leaves" normally the cause of this is due to imbalanced ph. In fact, what are your readings? I would like to know what is the average for the following: ec, ph, and moister level. What is your feeding and watering schedule? What brand of soil...
Stretch is generally considered an unavoidable evil, but some gardeners prefer a bit of stretch to allow budsites to fill in adequately. Buds with perfect density can be grown by controlling stretch.
You basically top plants to make them bush out instead of growing tall. But to answer your...
You can use a "green light" while you're in your grow room at night. I cover my grow room door with black visqueen plastic - so after I enter I pull it down. If at night or during the night cycle I cut on the green light. If during the day - no problems at all. Just don't interrupt your night...