what you do should be dictated by what you want in the fully grown plant.
Shoot for 3-4 colas per sq ft and that avoids over-crowding. Do whatever is necessary to get there. Top it, bend it, whatever... figure out the most efficient way to achieve your end goal.
Yes, anchor lowest part of trunk before you bend the plant over. Make sure whatever is looped around the trunk allows it to get thicker without constricting it... large loop etc..
Also, you can bend/weaken the trunk in a few spots to create a nearly 90-degree bend. If you bend it in 2-3 spots close together you'll also reduce the force applied to your anchor.
Anything under the bend should be cut off, as it will be weak growth compared to anything above the bend. Even if you go to extremes to let them catch up and level out with rest of canopy -- even then it will still be weaker growth.
So, don't bend it over until you have enough branches above the bend to share apical dominance and give you ~3 colas per sq ft relative to your light's footprint. Or, if you intend to top them all after that, you obviously need 1/2 of the branches needed at end.... so many ways to skin this cat.. and too many variables for a one-size-fits-all... work with deductive logical reasoning. Start with your end goal and devise a most efficient way to get there. Share vascular tissue as evenly as you can to get even distribution of buds.