Nirvana Northern Lights fem

hi all i have 4 Nirvana Northern Lights fem in a wilma that have vegged for 6 weeks if i put into flower will this strain go 2 x or 3 x the size and how long do people flower this for many thanks

it will get taller but not that much. 7-9 weeks flowering. Basicly the longer you wait for harvest: the more bud you shall get. But it also the longer you wait; the more downer weed you shall have.