I am a strict convert for the Gas Lantern Lighting Technique now that I've tried it on my last three runs. The schedule is as follows:
12 ON
5.5 OFF
1 ON
5.5 OFF
repeat
This makes it possible to keep the plants in vegetative growth while providing only 13 total hours ON -as opposed to running the traditional 18/6 schedule. I have found no appreciable difference for vegetative growth.
Then, when it comes to flipping to flower, I just remove that 1-hour ON period.
There is also something called the Diminishing Light Schedule, too...Basically, when you flip to flower, you run a couple weeks of 12/12, then you start to add an extra hour of darkness over a period of time, until you end up at something like 9 hours ON right before harvest. I have not tried this technique....yet.