you can top at anytime, anywhere in veg. i hve made viney monsters by toppint at the first or second node, and i have the cristmas candle look by topping at the 10+ node just before flower.

topping is topping, there realy is no right or wrong way. all about preference. but, imo, those topped early, then lst'd and topped again yeild the most of any yeild experiment i've tried (including extra long veg)

hope that helps...