You can get an auto-shut-down/hot strike preventer for ~$65 but you'll need to look around to get that price. I have theHLC-3 High Temp. Shut-Down w/15 Minute ON Delay by CAP. I got a 1 kilo flame defender for $52. Smoke detectors are cheap - $20 to $30. It's also good to have CGFI outlets. You can get a plugin extension if your don't have them built in to the sockets.

Those plants are young and your soil has nutes in it. Seriously, I would start at 1/4 recommended dose and work your way up. You can't take back damage but you can always up the does. Also, they look very happy. Why mess with them? They'll tell you if they need attention. Resist the urge to do things to your plants and keep it simple. The fewer variable s the better. It makes it easier to fix if it goes south. Also, remember that anything applied or corrective action taken will take 2 - 5 days to be realized in the plant. It doesn't happen over night. Finally, if damage is done (and at some point you will damage them, everyone does) remember that once damage is done it can't be undone. So look to the new growth in order to determine the efficacy of the remedial steps you take. You're doing fine.

It will get pretty crowded in there. SOG may be a good option for you. You can and probably should also simply keep the plants on the smaller side by flipping to flower earlier in veg. Research your strains and have an estimate of how much they will grow in flower. Flip accordingly. I run a scrog and started out that way on my first grow. So long as you do your homework you will be fine running a SOG. And look around here - there are some pretty dumb-ass people who grow this plant successfully. You clearly understand the principle of self-study and application of knowledge. If they can do it you should be able to start a nursery... Seriously. I have a couple good stickies in my signature but I'm thinking you have already seen those. I'll stop by again to see how you're doing. Update us as you go.