I don't really have any experience with those. I usually use the 10 second rule. Place hand at plant tops and if the light warms your hand within 10 seconds, move it higher. Real scientific, eh?
It's not really the time that you have the light on that's causing the bleaching, it's how close you have it. If you can raise it up a good bit. Otherwise, they're looking great. Keep on it!
It's been 10 days since my last update. Here they are. Once I get some horizontal space, I'll do some bending to even out the colas' heights. Should be in a week or 2 when I'm done harvesting the grow in the big tent.
They need some trimming, too. I'll get to that shortly.