Dont top it! It will be in shock for a week or two. It all depends on the strain, how big the pot is, or if its in the ground, weather, nutrients how much it will grow while flowering outdoors. This early pearl i have is like growing and stretching like crazy since shes been flowering, but i read that early pearl is known for this, also the weather here was too scalding for too long before, now it is ideal! So many variables and genetics, but they could double, triple? probaly not, normally its 3/4 from what ive experienced. good luck.