Hi,
You did not understand what I wrote:
* a factor of 2 is not a big difference in light intensity.
* and: instead of using "text" you should decide values as numbers for the according ranges. No need for exact ones, just exact enough to get a clue about the range and the thresholds, how to design the analog circuit, how to do the software.
Without numbers, just go the "trial and error" way. I cant help you with this, I'm no tinkerer, I'm an engineer.
Klaus