And it's not always .75 that is just a good rough guesstimate. Sometimes it probably is .6 or so. The key is having as even of canopy as possible. Don't really matter if you grow a bunch of plants really small, or a few huge bushes like I like. At least it has always worked for me. I used to SCROG, but anymore I just top a couple times and bend/break the branches into where I want them. I am hoping to keep about the same yield as I get now, or at least 1.5 pounds per 600 watts of LED. I hope they really do blow the HID's out of the water. I will be able to get at least 2 pounds per 600 if so. I can't wait to let you know here in a few months. I haven't seen very many large builds like I am wanting to do. All together I plan on replacing 4 HID's, so around 2600 watts of LED in a 5.5 x 12 room.
Do you think I should stick with just 3000k , or should I add some 5k in there too? I am also going to build a veg light, except it will be all one panel and probably around 4-500 watts.