As they are already on week 6, gotta think twice before going to top them, if you do, it's better to wait 1-2 week to them recover nicely.
If you have the time and patience, you can top, also remember the espace in your grow.
Now for LST you should also have done earlier but I don't see any problem if you still want to bend them!
I would go on LST rather than top, you can control their size better and don't need to wait more for flowering as they're already big as you said.