yeah bro, that looks like a prime target for a good LST, to get it even with the rest in height. . . of course, the radius the plant takes up will get bigger, so it will take up more radial room. . .
but it seems like the main purpose you would want to lst would be because you prefer them all to be the same height as opposed to the same radius. this way you can maximize your distance from the canopy to the light. right?
from the pic, i wouldn't even bend the tops over much, maybe just pull them out to the sides a bit. . . McBuds uses little clips from office depot to attach to the rim of the pots, seems to work well for dirt pots. then uses them to attach the strings.
If it was me, I'd just pull the two main tops out until they ares slightly lower than the rest of the canopy. . . if its growing faster, this will increase the time you can go before you might have to do it a second time.
i don't know how the stretch is gonna be, but if i knew one was gonna stretch a bit more than the others, i would LST it to be that much shorter than the others so like you want, I could get an even canopy for the final weeks when they really pack on the weight.
good luck bro.