Hey there Abava, great question ! see with autos everything is more difficuly mostly because they "stiffen up" quicker than autos, that means that any LST becomes more difficult because if you leave the plant too long it will "stiffen" up. Even after the 3rd week, i've seen growers struggle with plants that stiffened up quicker than they thought it would. So any LST, start it as soon as possible , and remember to anchor the plant's base. For topping, you need to look at the plant, see if it's still vegging and if it has enough nodes wait until there's four nodes and top at the 4th node for best results, dont do it too early as it will stunt the auto forever. Hope this helps ! 🚀