I let them most time grow until is see 4or 5 nodes then i top them above the 3rd Node, but there is another thing that catches my eye, your plant grows very dense and nearly " dwarfed" as if the lights are to strong/ to close to her, the distance between the nodes ar very close ( thats what i mean with dwarfing) that happens if the light is to strong/ to near . If you lower the output or rise your lights she will stretch more for the LIght
greetings