Well, I will pass this along since I just started doing it. Up to now, I've struggled to try to start off LST'ing and messed up my first try, so I've been doing the typical thing with my autoflowers which is to try to prune the heck out of it to get it to my liking (which was always a pain, I just didn't know any other way).
But, I'm in flowering stage with my current autoflowers after trying the experiment of simply topping after the 2nd node. I swear, I wish I had done this sooner. I'm never going back. I just top it at the fourth node and the result is basically as if I had LST'ed the thing perfectly and pruned/trimmed it the entire time to perfection except I didn't have to do any of that.
Two of them came out perfect in size and foilage, the third one still grew bigger than I had hoped (because of the space) but I have to do absolutely zero pruning to it. It's perfect.
I'd suggest looing that up. I'm going to try and find that forum I got the idea from but I think it's long gone.