1. when to start training - Soon as you can, usually week 2. Depends on the siz\e of the plant
2. When to stop training - You will always be adjusting throughout.
3. Do you ever untie the ties after final training or just let the plant grow out of them? - not done that, just leave them be & make sure the plant has enough growth room.
4. Is anyone against using LST on autoflowers? Not that I've heard of. Some autoflowers are better at accepting LST than others, so this would be the only time.
5. Garden wire vs other methods? I use garden string, others use those little bendy things. Whatever you have, or are comfortable with really.
6. Any advice appreciated . It can be a bit scary, and you will probably balls it up sometimes, but that's ok. Go slow, and steady.