Just want to put this out there, for you to consider. The plant will not begin to flower until it becomes sexually mature. Period. As a general rule you are looking at 6-8 weeks from seed to get there. The plants are at 4 weeks and have not sexed yet. So you can wait lets say 3 more weeks at 12/12 for it to mature and start to flower or you can let them continue to veg 18/6 for 3 weeks till they are mature. Thats 6 hrs per day for 3 weeks of growing light it will miss out on if you flipped now. As tight as those nodes are on your plants, the stretch is going to be minimal. Generally speaking a 4 week veg is for mature clones.
I am curious though, what strain 28 days from seed completely fills a 9sqft scrog and ready to flower? Not saying it does not exist, more like where can I get it.