Yo BNB420! Haven't grown 12/12 from seed so can't help you out there, but I can tell you which one's I would try, haha! I'd go with NL X Skunk (love NL and Skunk so win-win) and Pineapple Chunk (Have seen excellent grows and yields with this strain). End of week 10 sounds good, if you think they need a few more days, no harm there either. I like to let the plants tell me when they're done. Can you check the trichomes for amber as an indicator? I'll try to find you a link to this easy LST method that I'm actually trying out right now and it's working pretty well. Basically it's just (scotch)taping the tip of a big fan leaf blade to the side of the container, gently pulling/bending the plant down and to the side. Pretty nifty. I don't know about the cold water, but I like to leave my plants in the dark for 36-72 hours before I chop them, letting them dry out actually after a good flushing. Hope that helps some, but remember it's just what works for me. Everything you're doing now looks great by the way, so just keep it up and experiment here and there, that's where most of the fun is anyway. Peace, good luck!