Low Stress Training advice? When to start? What factors used to decide?

First of all make sure she's healthy, she looks to me like she wants more nutrients, check your ph is on the correct range. Moving the light further definitely helps. When she is looking healthier and a little taller just bend the stem over and tie it down to reveal the other shoots. 👍👍

oh, anything below the bend is most likely a lost cause, so the lower the better.. wait for at least a strong root system.. 6-7nodes? i've done it before, but you damage roots and it'll stall out for a long time in shock

the idea is when it is horizontal, you'll get even growth from nearly all auxiliary nodes.. the plant dedicates the most resources to the tallest portions of plant. So, as long as the trunk is bendable, it's never too late. Too early can damage fine, immature roots. Use an "anchor" in the opposite direction of where you intend to bend it toward. Don't just randomly pick a direction. Look at the axial growth on the bplant, go between that so that each side has an equal ability to grow vertically after the trunk is bent mostly horizontal. So, you got an anchor for support. Now, slowly start to bend in multiple spots near base.. gently between finger and thumb.. just try to get it to bend a bit, then move up a bit furhter and bend a bit more... create a short arc to 90 degrees. tied down terminal bud, and if it is tall, you may want something to hold down middle, so it doens't arch too much... any growth off the top of an arch will dominate growth and defeats the whole purpose of doing this. so, get the apical meristem (trunk) fairly horizontal. Doesn't have to be perfect, but the closer you get the more even the growth off of it. it'll alawys be fighting to grow vertically, so it has to stay on nearly until end. You may slip it out futher or add a new tie down.. just depends on how large you are going as far as that goes. any growth that is taller, gets ore resources.. bend it down, if you want other things to catch up. Make use of pruning to spur auxiliar growth or stall that branch in addition to growing the lower buds out.. etc etc.. manipulate the plant to do what you want. it acts in predictable ways.

Here's a link to a site to show you everything you could want to know about autoflower lst training.. https://www.autoflowering-cannabis.com/autoflower-lst/ Happy growing! 👊