Thanks for that info. I'm a long way from being a "master grower" and haven't gone as far as to calculate my PPfd (honestly, I only conceptually know what that references). In my simplified world of trying to balance grow medium, water, light, and nutes, I'm focused mostly on overall yield as my measure of success, with grams per watt being a reference for how efficiently I'm going about it. There are so many variables, I can't imagine how many grows I'll have to do before I can turn up/down my dimmers a percentage between grows, and see a predictable change in outcomes. Some day maybe I'll have everything else nailed down, and the light itself with be the only remaining variable.
I am curious among those I consider to be the elite growers, what their focus and goals are. When they tweak their well honed system, what specifically are they trying to improve? Most of the conversations seem to be about weight (either overall or in relation to watts), I'm also curious how light effects THC content. That's probably being discussed somewhere, I'm probably spending too much time in the DIY threads...