Darth_Glentract
The Truest Sith Lord
I don't even consider Jacen gray at this point. He's a Dark Jedi now as far as I am concerned. I think if Luke really knew what he has done I think he would certainly hesitate to make him a Master anytime soon, even if he is more then strong enough to be one.
I certainly thought that the grey was stronger then the Light, but then I thought about how Luke doesn't seem to lose any power when he goes back to the light after he was grey. And even by the end of DN, many of the Jedi still seemed grey to me, others like Jacen Dark, and only a few actually seemed to come with Luke back fully to the light.