I don't really agree with topping the plant, you're cutting off the main growing shoot.. granted, the energy is distributed between the other colas.. but put it this way, if you had scrawny arms.. would you decapitate yourself to get buff? keep the main cola at all costs,

Nosehit nailed it, during the flowering stage your plant grows about 30-40% of it's original size (meaning from when you put it into 12/12)

So if you want 2 foot plants that will yield about an ounce of dried smoke.. put them into 12/12 when you think they're tall enough... about 1.5 feet?

LST is a great way of training the plant to grow a certain way, it opens up the lower branches so that the colas can get alot more light...and you still keep the main cola

i did this to my plant, as some of you know... and it work extremely well..

Enjoy, Bob.