If the efficacy isn't 2,8 or higher, i'm not using it unless it's some 100-150w or lower light. I have a less efficient 150w light i use for early vege. It has a 10-100% dimmer knob.
Efficacy is king. Directly correlates to longevity too.
480w and 650w lights i use are all white LED with some 660nm mixed in. The rest is unsubstantiated as of yet. I've seen all sorts of conflicting info on UV lights. Bugbee has some indoor tests that revealed potential, but then other research shows nothing useful amounts from it. Bottom line, whateve rimpact it has, i'm not paying through the nose to get it. It is small and irrelevant effect as far as i am concerned.
I'd still favor a warmer CCT, but even that i'm not certain of being extremely important anymore. I'll be comparing a 2900K and 3400K run this winter. Not scientific in anyway, and i'm not concenred with "statistically significant" if it's some tiny number not worth worrying about. statistically significant can still be a total waste of time and effort. just depends on context.
Stick with LM301 didoes. B or H it absolutely doesn't matter. From their serial code you can reference the binning in the spec sheets on samsung website. it can make a 10% different in efficacy and still be labeled "lm301" white led diodes. They are similar but not all lm301 are equal. just one more wrinkle to account for.
That's okay, even an inferior bin will be an excellent efficacy if you run them as they are driven in the spec sheet testing. This means anything that deviates from 0,25 watts per diode is underperforming compared to spec sheet at samsung com. Any advertising that lists the samsung specs while driving them harder is a fucking liar and they know it, lol.
You probably won't eclipse 3,0 umol/J with anything store bought -- HUGE red flag if advertised as such. There are some chips that are being run under spec sheet power, and that comes with risks too., Samsung will not guarantee the light produced when under powered. you'd need some spectral analysis to know for certain the SFD is keeping it's integrity (the weight of all the wavelengths, ie that curve you see with every light showing peaks at red and blue wavelengths - the curve is the visual representation of SFD)
But back to those odd underpowered chips.. they theoretically will get improved efficacy and eclipsong 3,0 is that much easier. Normally the only thing going that high is the 5000K CCT diodes and thats too cool to be using exclusively on plants (cool is a higher blue ratio, not physically cold) The 3000K and 3500K might max out at 3,0umol/J but your 660nm reds and anything else will just average it out lower in nearly all cases.