It is true that if you keep bending your main stem during the veg cycle that they WILL bush!A guy at the local MM center showed me that by just a nice bend each time you water works great and no need to top.GL
Not sure if this is completely true, but I topped one of my plants once, and then did LST a few times and everytime I bent the main stem over. It is so bushy there is barely enough room left in my grow box for it to fit.