Yeah like I say, veg them until they are HALF the maximum you can deal with. They double in size in flower sometimes more, you will have to tie the branches down.
So, let's say that with the lights at their highest setting, you do the "back of the hand" test to see how close your plants can be and find that point to be, let's say, 45 cm from the ceiling, you have 1.95m potential grow height. Then subtract your pots and stands from that, for arguments sake let's say 45 cm again, giving you 1.5m grow space. So you can veg them until they are 75cm tall. Topping them along the way makes them grow more bushy and short which will help max your plants out.
Of course, you need to do the maths for yourself, those are just made up numbers there, but you get the idea...
