hmm, dunno, that seems strainrelated, im not much for topping, but i accidentally topped a young sativa the other day.
it had 3 nodes (apart from the sunleaves) and i flipped off the top while i was bending it bit.
well, it didnt stop growing, grew very quickly into 4 tops.
the reason for this, was it allready had budsites (well, future budsites(or potential tops))
And the distance between each internode was so small that the upper budsites didnt get priority over the lower.
now, if i waited longer, my experience with topping tells me, that by then the distance between nodes would be such that 2 tops would automatically get priority and leaving you with 2 tops.
the only cases where ive seen different, was with a naturally bushy plant (denser more indica plants )where about 4 of the lower budsites had grown to about an equal height.
and being about 5-6 nodes (or so, wasnt really counting, might have been more) and where if you cut off the (quite alot larger) top, these budsites would automatically grow into 4 nicely spaced tops.
but, you´d be sacrificing quite some time with cutting that top off (though it makes a nice clone) and need to spend some time in veg to grow those lower budsites to proper size (bigger tops, bigger buds)
whereas with lst, you´d keep that big top and end up with 3 slightly smaller tops (almost the same height and size) along with it (or however many you want)
in less time, but with more work (Which i understand was ub´s objection to this)
i would think, topping later for bushy females, topping earlier for plants that have allready lower budsites (as some plants grow to some height without growing anything but the top and fanleaves, the lower budsites appearing maybe in 2-3rd week, making the internodal distance too much to get anything but 2 tops with topping (unless you topped more than once or used lst along with it(topping for 2 tops i find absolutely pointless though and really topping for 4 unless you veg them out properly before flowering)
and lst or scrog or straight up for the plants that develope lower budsites later (3rd group i mentioned)