I may be jumping the gun here, but when should I s...

Typically you wanna wait till the plant has 5 nodes before you wanna start topping a photo period plant . I say this because you wanna wait for the tap root to be long enough . Once you top a plant it removes the steroid that pushes it to grow upwards and makes it grow side ways . With that being said it also make the tap root grow much much slower now and the little side roots are whats going to expand vigorously . You can top sooner but you run the risk of having a much smaller plant in comparison . If you look at my GG#4 grow you can see that example set out between the 2 that I have in that grow . One was topped at node 4 and one was topped at node 5 one ended far bigger then the other even tho the training methods were almost the same . Also allowing your plant to be a fair size 5th node or bigger will ensure that your root system is strong enough for a speedy recovery so you can determine if you want to top again or if you just wanna let it grow from there out . I hope this information helps you on your quest to becoming a master grower ! -Happy Growing!