Google "full spectrum led layouts" and check out the first hit.
I did. The first hit took me to a thread on another forum that was clearly written by someone who does not understand the idea of full spectrum. It wasn't the worst thing I've ever seen, it's probably above average, but there's plenty of room for improvement.
First, in the couple examples I looked at there were way more emitters than needed. One example is the 20H, common thinking is one LED per 15 sq in of surface or about 16-17 LEDs on a 20H. That author suggests 30 emitters.
Second, the writer suggests that this applies to Cree or Luxeon LEDs. I've use RB XT-Es and Luxeons together on the same fixture and they are not interchangeable. I would not choose the same blue LEDs to go with a XT-E RB that I would with a Luxeon RB. The number of RBs speced for a 20 H is 50% more than I would have used (or have used on my own 20H) unless you like a very blue tank. I would certainly use on over the other based on it's spectrum, but I'm sure I could build a decent fixture with the other. In fact, while the Luxeon is the better choice for corals, the Cree is easily the better choice for a fuge light as the spectrum is more suitable for plants, including macro algae.
Third, make up your mind, 5000K or Neutral White. Buying LEDs based on color temperature is always a bad idea, it says little about spectrum with other types of lighting and even less about the spectrum of an LED. Color temp only tells you the average of the spectral peaks produced, not what peaks are present. A 5000K LED is the cut off point between cool white and neutral white, some manufacturers even make both. Either way, a 5000K LED had a predominant peak around 450nm, that means that half it's output is RB. That means more RB on top of too many RB. This auther must really like blue tanks. Using a 4000K NW or even a Warm White will give more of the spectrum from 500nm to 700nm. The goal was "full spectrum," remember?
Fourth, it's "violet" and again, wavelength matters. The entire part of the spectrum called violet is very important to photosynthetic organisms, much more important than the builders of early LED fixtures had thought. Unfortunately, many hobbyists can't wrap their heads around the idea that violet is a color of visible light and has nothing to do with UV, so manufacturers have taken to calling their violet LEDs "true violet." I find it sad that someone would build a fixture without a basic understanding of the spectrum they are trying to produce and knowing the difference between UV (<400nm) and violet (400-435nm or so) is a key part of it. If "TV" means anywhere from 400nm to 435nm, which wavelength does the author suggest?
Fifth, OCW. I don't see the reason that these are so popular lately. Yes, 465nm, 495nm, and 660nm are all important, but not in equal quantities and in some layouts you wouldn't need to add all of these emitters. For instance, some bins of Cree RBs peak as high as 460nm, there's no need to add a 465nm emitter in this case. OTOH, a fixture with 5000K whites is going to be lacking in wavelengths above 600nm so adding 630nm is just as important as adding 660nm.
Like I said, this isn't the worst information in the world, it's a lot better than the old RB/CW fixtures or even the RB/NW that followed. The author is correct that you need to add violet, blue, cyan and deep red. The info falls short in it's lack of discussion of "which RB,'' ''which violet'' and ''how much red, blue and cyan.'' It also failed miserably with a poor choice of white emitter, the lack of orange-red and the use of nearly twice as many emitters as required.
For anyone that wants to build a full spectrum fixture I'd suggest the following, instead of researching what other people have done and trying to guess who did it best, spend the time learning about the spectrum that is actually used by the inhabitants of your tank and select emitters that can provide the necessary wavelengths.
