Try an auto. I've been growing and smoking auto Ak47 for about a year now and it's pretty potent for an auto. I have a high tolerance, but everyone I've let try it has said it kicked their ass. Been growing two at a time in a fridge under 250 watt hps (just upgraded to 400). Plenty of room in there for two. They need elbow room, don't even let them touch each other if you can help it. I had five in there one time and they stretched like crazy and that's the last thing you want to happen.
There is no sea of green method for autos either, you let them do there thing. The auto AK47, if given the elbow room, will almost SOG itself with it's lower branches coming up like satellites encircling the main cola. That main cola can get as big as a dry ounce (I've had that happen only once. Usually get a bit over a half from the main cola with the whole plant coming in at about an ounce and a half.)
I only have 30" of clearance under my light.