Very interesting read...
My trichs were at about 40% amber when I harvested two plants of unknown genetics at week 12 of flower. I was growing under 2700k CFL's.
The smoke, now dried and curing, produces an extreme couchlock that sends tingles down the backs of my legs and "sits" on my forehead hardcore.
I agree that trichs cannot be the only judge. But I also think they have relevancy. I have a scientific scope with a 4x, 10x, and 40x zoom. It has a 1/2 sqaure inch viewing window, so I can see ALOT of trichs at one time. At no time in my grow, and I checked all the time, did I have a large AMOUNT of amber trichs except at the end.
While its true that there were amber, cloudy, and clear all over throughout the grow, they did in fact turn so that there were very few clear (perhaps 10%), with the rest being an equal mix of cloudy/amber at the end.
I observed a noticable shift from weeks 8-12 for sure, watching clear trichs turn cloudy and or amber. I read this thread long ago and kept my mouth shut because I didnt have much to offer. However, I can say that the trichs said harvest week 11, but I waited a week longer and they did "look done."
Would I have thought they "looked done" sooner without the scope? Or later? I can't really be sure. So my conclusion is that while trichs are not a DEFINATE science, IMO, they both serve as an excellent guide and emperical data to confirm that they "are done."
My 2 cents.