I personally wouldn't top any of my plants now knowing what topping them does, I'd simply train them instead.
Cannabis basically has 2 brains, 1 at the tip of the tap root, 1 at the tip(top) of the plant, cut it off and it takes about 8-10 days to re-grow the brain, during this time you won't see any growth really...basically just delaying your grow
Thats Cool. I didn't know that!~