Hello P Well I don't know about the type of lights you are using, hopefully someone else can answer that for you
It depends on the strain a bit but I always like to end up with plants about 36 inches (one metre) in height, so I always incuce flowering around 18 inches "give or take an inch".
As for re-potting I think if there standing ok by themselves then re-pot at the same level, that's what I would do anyway .



love mand xxx