As you are the most knowledgable here, I have two more questions if I may.

1. I can find nothing in the science that suggests a 6 or 8 to 1 red/blue ratio. Is this just attempting to copy HPS/MH spectra or are there real studies that support this? On one advanced cannabis board (engineers not growers), the conclusions was a blue to red ratio of 1.5 to 1 is best, while the absorption graphs look like it should be closer to the inverse, but nothing as extreme as all of the popular LED lights.

2. As you stated, and I have come to the same theoretical conclusion, that it's the photosynthetic photon flux density that is most important.

Let's assume these mfg numbers are accurate for this discussion. If I have a white LED that outputs 100 lumens/watt and has a higher total PPFD than either a 75 lumen/watt red or blue LED, (sorry no spreadsheet) why would I not go with all white LEDs? The spectra is something roughly like 40% blue, 10% green, 20% yellow and 30% red. (Don't hold me to those numbers.)

Any light you can shed (no pun) on these topics would be greatly appreciated.

Thanks!