Hey pal.
Topping is a taboo on here
Yet I've had some of my best results from topping and stripping runtz (autos) as the nodes weren't growing.
For example my Lemom Pie was a pure runt tiny little thing. Topped her above the 3rd and stalled the flip and she vegged out at 50cm (will add her flip this week)
But, I only do that now in very extreme cases were I don't see any growth.
LST is fine. You want to lei your plant take its natural shape. And it'll all be more than pliable to move them nodes where you want them
But, don't top an auto for your 1st. Not until you see how fast they flip. For there to be any good growth on them you have to do it within 10 days or so. So you'll only get 4 sets of nodes and then hope you get another 2-3 weeks and hope (again) she doesn't flip.
Once an auto reaches 40 cm has a nice bit of girt..LST'ed out well. (If you using pots. Just drill/poke holes in the side, make a bow not as you do not want to make an hangman's or anything that'll cut into your nodes/stems when they fatten.
I know you didn't ask about this:
So, for defoliation. If you are finding your nodes. That the fan leafs off as this will stop putting energy into making leafs and it'll start growing your nodes.
Feel free to DM me regarding any of this. And good luck and enjoy.