I’m thinking that I would do well to buy two 3000k QB288v2 boards, a heatsink, and a controller and use em to flower in in a 2x4 tent.
Sound good?
Go for 4000K if you can get them. I use 4000K samsung strips with the lm302b in my DIY led setups (same as the quantum boards), I can't say how they compare to the 3000K lm302b chips as I have run 4000K from the start however the 4000K works well for me - I've also heard a few people who got 3000K say they wish they had gotten 4000K.
It all sounds a little counter intuitive, given that for many years using gas discharge lighting we all considered MH in the 4000-5000K range to be only good for veg but LEDs are a little different. to understand why take a look at the spec sheets from samsung for the lm302b and compare the spectral analysis chart for the 4000K with a spectral analysis chart for a typical MH lamp and with the chart for the 3000K lm302b chip. The area under the curve is the total output and you'll see the 4000K chip has a lot more overall area under the curve than the 3000K and you'll also see that the peak in the red part of the spectrum is not that much lower than the same peak for the 3000K.
Just my two cents, as I said I've never done a side by side so I can't say for sure but it's looking to me like as far as the lm302b is concerned the 4000K is best overall, at least on paper.
When you get your controller, make sure you get one you can dim.
If you don't end up getting quantum boards make sure whatever it is you do get runs the lm302b chips, they're currently the best out there for luminous efficacy - however it would pay to make sure whichever product you get isn't over driving the chips at the expense of efficacy - the QBs do that pretty badly if you run them at full power and only deliver about 180lm/w. Turn them down a bit and you can get 220lm/w (at least in theory).
