K1Ng is right on the money. I've got a 600 watt hps digital ballast and 6" easycool reflector that rocks man. I personally decided to set up my room and learn how to grow before I start messing with hydro.
I've seen my flower room close to 80% and I've never had a bud mold. Lots of air movement like the rest of these guys has said. My first grow it scared me because everyone says 40% so I bought a dehumidifier and it kicks the temps way to high so I don't even bother.
It's better to do before 12/12 but if you just put them in give it a try. I wouldn't do it if they have been in there a couple of weeks. The plant won't have time to heal itself before it starts budding so you may end up with some small colas.
Can you trim her back? Thats what I do to mine. I flower them when they get to crazy but don't be afraid to trim her back. I would not trim more than 15 or 20% of at one time.
I used a wet paper towel folded several times, put it into a zip lock baggy and put the baggy on my computer monitor. Within 48 hours they should start popping. You have to be careful when you plant them, put the root down. Sometimes I would screw up planting them and the root grows out of the...
If you don't top your plant doesn't have to repair itself. I've done it both ways and really can't tell the difference to be honest. I'm pretty lazy so I usually have to top them because I waited too long before I tied them down.
Topping works but I would recommend LST. Here's the link to the faq info about topping and pruning. You can see LST at work in my old grow journal, links in my sig.