When you get isometric growth or around 5 nodes from what I've read and been told.
I had 10 plants, I topped half, 5 of the topped were male
I was left with 5 normal and one topped, 2 normal died in the last week or so of flower.
Out of the four remaining the topped plant yielded 82g with the 2 normal yielding 100+ and the forth normal yielding 74g..
Much love and Good luck