I was going to say that you're going to have too much growth but it looks like you flipped them just in time. You're on the right track and as long as you maintain things you should yield a pound or more even. Just make sure you get yourself a lot of air flow going in there, and perhaps even consider removing some of the fan leaves that are blocking your buds from the light. Things are going to be tight in there, but if you have proper airflow and can keep your humidity below 40% or even 35% you should be well on your way to a bountiful harvest my friend.
My first indoor was in a 4x4 tent with a 1000w. I started with 5 plants too, but one ended up getting sick because there wasn't enough room/airflow. Once I took it out, the other 4 did amazingly. Each plant pulled around a QP give or take. Had I started with 4 in the first place, did it under a screen like you did, and took better care of them, I should have been able to get much more.
A 600w light under these conditions should be able to pull 1-1.5lb if things are optimal. From what I'm seeing, things are looking pretty damn good in there. After you get this one under your belt, I'd recommend looking into a 1000w and running only 4 plants instead. They'll fill out your space much more evenly than 5 will, and with proper training you can get 2lb+ with adding a 1000 watter.
Those last photos you posted are looking really really good though. And you said newbie too? The amount of due diligence you've obviously done before hand is clearly showing if you're actually a newbie. I'm expecting at least 1lb if you keep things up, I'm actually going to sub just so I can see
The best part about having grow journals is that you can post about things the instant you have problems and get some feedback going. Conversely, if you're thinking things aren't going too well you can always post photos for re-assurance. Always helps me when I get too stoned and overthink things haha.
Very much impressed so far though, and I see this journal actually coming to a happy ending.