This is a great place to start. @dbrn32 loves all things light and is great about answering any questions you may have. There’s a fair amount of BS’ing but there are some real gems in here too. My build (and others’) are documented as well.
My lights, to be specific, are Bridgelux gen 1 EB modules (10 per fixture), 560mm, 3,000K with a peak of 240 watts per fixture with a footprint of 22" X 36" times 3 to fit a 48" by 72" grow box. I can turn them down 50% to 120 watts per fixture. Luminous efficacy is around 153 lumens per watt at around 75% of peak output. Higher at the lower wattages. In comparison; your average Amazon light does around 75 lumens per watt. Typically I run 600 watts all up (200 per fixture) for most of flower.
I went this route because I had access to a considerable amount of aluminum which is 50% of your expense when building lights. So mine cost just shy of $200 for each fixture but would have been double that if I had to buy aluminum.