I guess the main question i have now is....

Is it practical to LST now? I had it in my mind that i was going to LST all of them and give them a good thorough vegging but if they're staying this squat, would the difference be noticeable?

And another question is when they say that LST promotes 'secondary growth' what does that mean exactly....because my bottom leaves are growing out fine, pretty much equally if not more than the vertical growth, but at the point where the branch meets the stem there are a whole slew of other leaves coming through.......is this the secondary growth that i need to promote, or are the fan leaves at the bottom just supposed to get bigger?