This is a hotly disputed topic. I topped one for an experiment. Didn't change much, but the one I only defoliate is doing better.

From my understanding in autos it’s not good to top your plant without putting it through heavy stress Might end up losing her . Autos are very picky they do not like to be topped or transplanted to bigger pots. You can LST them to open them up but that’s about it

Depends on your strain but yeah you can. A small and low yielding strain won't get there even with a miracle, but high yielder medium sized plant with topping and lst will get you about 500g.

so what do you think about harvest with topping and without topping ? can i get 70-80gr with using lst techniques and nutrients?

Yeah, like grower+homie

Growmie?is it some kind of nickname for amateurs?I liked it if you count me as a grower.I'm proud :)

Topping an auto is alright if you do it the right way, you should do lst too after topping. If your plant is a good yielder the lst sure as hell will help. Best of luck growmie.