To top or not to top

I have just two plants growing as a first run in my new grow room. Got as clones 3 days ago. An Alaskan ThunderF*** and a New York Diesel/Skunk.
I would like to attempt to top the NYD, here are some pics, is it ready for topping? What exactly should I cut? To late? Its about 10 or 11 inches tall, but not much growth it seems.

Top it!! I topped mine at about 9 inches. You're going to want to go down to the nearest split in the staulk. Get as much as you can, otherwise it might not take (I had this happen with a couple of mine).

I have topped plants a few times - never found it made any difference to yield - compared with plants that weren´t topped.