Hi SotallyTober
You don't have to remove any plants, and there's no particular advantage to individual containers over raised beds/compots as long as you are providing enough volme for roots.
As others have mentioned, you were extremely overlit, with about four times as much as you needed. That much light will cause the bleaching you are seeing.
"Optimum" levels are just that - the best it can get. Any additional light beyond "optimum" is at best wasted and at worst (as you are seeing) detrimental. Optimum lighting varies by cultivar and conditions, but a single 1000w light is plenty for your space.
Everything else looks like pretty standard SOG technique. 30 plants in 16 square feet is a little less than 2 plants per square foot, which is actually kind of low density for SOG. Your plants look about the right height.
If your temperatures are really that cold then you could benefit from a space heater. Ideally, you would like temps to stay between 70 and 80F, but 65 to 85F is acceptable. The temp range you reported is enough to seriously inhibit growth. You'll also want to know your relative humidity and try to keep it around 50%, at least until the last 2 weeks before harvest when you can let it get lower than that.
You may or may not have nutrient issues (burn or deficiency). The low temperatures that you have been running ihibit nutrient uptake so that you can get symptoms of deficiency even if there are adequate nutrient levels present in the soil. If you can describe in your feeding program (product names, amounts, frequency) up until now, we can try to help you get that sorted out.
Buzz is right that all of the "drainage improvement" you have added to the bottom of the box may be actually causing drainage problems, and the others were also right when they suggested that you need drainage holes. The best thing to do right now is to drill some drainage holes. In the future, don't use rock/perlite layers in the bottom of the container.
The good news is that you still have a month to go with these clones, and this is the most important time. If you get the lighting, temp, RH, drainange and nutes under reasonable control now, you can still salvage a harvest out of this grow.
If everything goes well from this point forward, you can probably expect 10-12 grams per plant.
penguin