I'm growing Himalaya Gold from Green House Seed Co. also and what they say about height is true. Fast growing and hearty. I put my first two under 12/12 (600 W HPS) at about 4 weeks and I think that was a little too long. The next 4 I put under at two weeks and they are staying fairly short but haven't flowered yet and might still kick it up before they do. They smell great already and look good too.
I would also consider getting a better hood, an AC one that you can vent through to help with your temps.