Lost me when you said this
gram per watt is so inconsistent no real growers are measuring that . Way too many items to factor in such as veg time, time of day using light ,other electronic sources aiding the grow, strain, feeding schedule , etc.... Here's an example
I veg a plant for 1 month, flower for 2 months total yield = 40 grams
I veg a plant for 2 months , flower for 2 months total yield = 40 grams
Those two plants have the same gram per watt but completely different amounts of light used because vegging times are different. Gram per watt is basically a pissing contest.