I have not had any issue's with how tall they get. I have vegged the gg#4 to 87 days. I have done this a few times. That plant is in flower now. She ended up being 6'.6". If you have the room veg her asl long as you want to. just dont over crowed the room.
My plants look similar to dans just much taller. We cant take off the branches there are tops still attached to them. Any branch that doesn't have any flowers on it is cut off.
6'6" plants ..... i've got 50" to the lights !!!