Rhiz is right on the even light of a parbolic works like a charm.
Take any photogram and darken a print and you will see the flat spots and hot spots of box parking light devices.
I always love things how they work and bla blabs (that just talking and no data to back it up]
I have used parabolics for a few decades and average 0.468 grams per watt day in year out. In a plant them in buckets chop to fit, bloom to harvest.
scrog is to much work and I grow with a computer and lazy.
grams / watts/months
if you have 1000 grams finished using 1000 watts / harvest every 2 months its 0.5 g/w/m
You must add months as you could grow a plant for 2 years and bloom for 4 weeks and get one hell of a number.
"grow for effecency , the fun comes at harvest" SanClem