For what it's worth, here's this not-so-experienced grower's opinion on that..
First, I haven't seen anything on the subject that references or establishes scientific fact. It's all theory (and sometimes less than well informed theory). The bottom line is do whatever works for you.
I don't buy into the idea that LST can replace defoil at any stage of growth. Both are important and effective techniques. Sometimes it's a better idea to remove a fan than just move it out of the way. Other times that is the only option. For example, my Cheese is just starting to think about pre-flower. Still stretching and all that. There are some large fans that are obscuring some potential budsites very near the top of the plant. I could use LST to just make the branch horizontal, which would expose the other budsites, but lopping off the fan that is blocking the light seems much less stressful for the plant. If height was a concern, LST without hesitation. That's not the case here.
So here is also my less-than-well-informed theory. Just food for thought... The plants will build fans no matter what is in the feed. It's what they do. Do they "need" the fans? Well, no reason to remove them during veg UNLESS you want to increase the light to a potential budsite. Sometimes you just can't do this with LST. And no real reason to do it during flower unless they are blocking light from where you want it to go.
I am naturally inclined to let the plant do what it wants and only stepping in when I have to. So take my opinion with that in mind.
I've not tried lollipopping or any other large-scale defoil method, so I have no opinion on it. There is no denying that it works, and there are plenty of grow journals here documenting that.
Here's a pic of my now overdue GG4 grow. I think we're on day 76 now, and flowering has just started to take off. And take off it has. There are more nodes with budsites than those without. If I can nurse this thing across the finish line, I am expecting a pretty fat yield. My approach is as I described above. If I see a budsite in shade, I look for the offending fan and it is gone. Other than that, I am not convinced that the more fans I remove, the more energy the plant puts into flower production. Like I said earlier, the plant is gonna do what it's gonna do. If anything, in my opinion, removing fans has zero effect on bud growth outside of allowing in more light.
You might be able to see the network of pipe-cleaners in the forest. That's how I do LST. I bind the branch to another branch, so it can grow with the plant, and not hold things to a fixed height.
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Anyway, this is all just my opinion, and is based on limited experience but a good deal of research.
Hope this helps.
trail 
