light dep.

I'm going to try a light deprivation next year using a 4x4x4.5 blacked out greenhouse for the dark time. sunshine for the other 12 hours. Was wondering if I would get a better yield using a s.o.g. style or growing one big plant by dropping the growing container below ground level like I have this year to keep the plants from growing over the fence.(yes, I topped them as much as possible). Don't think I would have the height problem because they would be in bud mode 2 out of 3 months...my thanks for any input.