I was wondering this my self a few weeks ago and I decided to wait until they go outside. I was brought to the point by another member that if you top now, the auxiliary growth may not be strong enough to handle the outside conditions even after hardening off. I topped a couple and left the rest alone. If you have a few to play with then try a couple out, If it works, awesome. You know for next year. If not, then you didn't mess up your season.