As a headstash and personal medical grower, I grow one or two plants at a time so I veg/scrog plants at 18/6 for months and months to get the desired canopy. My theory is that if I get in trouble, the cops will look like fools busting a guy with one or two 16" tall plants in the closet. If I had a SOG with a few dozen seedlings they would blow it out of proportion.
This Power Kush plant below has been growing since august. At one point it was left for dead, then I decided to revive it and scrog it using an 18"x30" piece of white wire Lowes closet shelving. I flipped it to flowering about 4 weeks ago and the buds have formed nicely. There are about 50 mini-colas all together. I'll probably get 5 jars off this. Power Kush is a moderate yielding plant so this is pretty good I think.
I might move to 20/4 to see if that works but I'm getting good results using 18/6 with big CFLs before moving to 12/12 under a 600 watt Lumatek/yieldmaster II (dimmed to 400 watts). The plants are either DWC or drip with drip producing the best yield. As you know there are so many variables but I am having decent results. I pulled 9 jars off a Northern Lights/Big Bud scrog plant last month! Took over 5 months from seed to bong though.