@grownsince79 is the man to ask about topping. I have always found his advice very sound.

I top 4th or 5th node¹. But I don't top outdoor.

1: most of my plants are about 8" tall when they are showing 4 or 5 nodes.

If you top them when they are really small it slows them down more so your veg will be longer. Personally I'm not in a race so I top them as soon as I can. It definitely stuns them a bit if you wait it out they come back and keep on growing. As soon as she bounces back again I top again. Its a house of pain around here homie she gets no breaks! I like to get as many of those Y splits as possible. Then I put it through the trellis for support like the picture below. I would let yours go just a tad longer then you can top it and make a nice clone off of the piece you remove

Yea I ment to have this one out in a 25g fabric pot already but there was some complications with the site. So I'm doing my big grow next spring(I'll start the seeds mid winter) and put them out when they are 3+'. That way I know they'll be some monsters. This year I just want to see how big I can get this lady in the 2g pot she's in.