Its a WEED!! Cut the top off it, it will recover! Ive done both lst and topping in MANY forms. Topping is what i reefer to when Im growing in 7' ceilings. Once you top it, they like to get bushier instead of taller. I usually wait and top
above the 3rd real leaf set. I think other factors have more to do with yield than topping. I top mine any time before going into flower. I mean really, you can abuse the piss outta these ladies while in veg, and they grow right thru it. Occassionally Ive topped an out of control lady, mid flower. Problem is, you lose yield when you top so late because there isnt time left in the cycle to recover and create new bud sites.
As for lst: i dont do a lot of that on my normal gals, whatever room i save vertically, they take up horizontally anyhow. Although, if you bend a gal over, she recovers within 8hrs usually! My mothers, I top them about every 2 weeks, and Ive also LST the crap out of them. I use 1000w hps', so I dont worry about light penetration on platns under 40" tall. BUT, if i was making one lady as big a yield as I could, indoors with low cieling, I'd LST that thing so it would be 3 feet long HORIZONTALLY, then flip to flower and lst/top no more. Ill update a journal soon, i think ive lotsa pics showing extreme lst/topping. O' btw, I harvest about 30 clones per mother. impressive is that theyre only 12" tall and 6 wks from seed when i get those numbers. Lets just say that its rediculous easy to lst and top a gal and generate hundreds of clones from her.