Going into preflower has zero to do with training, watering, light, nutrients or anything else, only genetics.
That's it. The unique individual genetics of THIS particular plant, nothing more, nothing less.
Auto flowering is a function of genetics.
It (generally) can not be controlled by any type of other external factors and is purely related to the plants age, roughly 3-4 weeks.
This is basically because the plant makes the decision for you as to when it will flower, be it at 3 inches or 3 feet tall and it is because of this unpredictable nature that I gave up on autos. I now concentrate solely on photoperiod plant with their controllable (by me) flowering time, as I can get them to flower exactly when I am happy with their size, rather than have a 6 inch, 3 week old plant start flowering and yielding only a few grams. They just don't meet my requirements whereby I want to get maximum results from each grow, not spend 3 months waiting for half an ounce.
Unless grown with bulk light and generally hydroponically or in coco coir, which is basically hydroponics anyway, autos really don't yield enough for me to bother with them. For me, they do not have any advantages over normal photoperiod plants, so why grow them?
If you want to grow as naturally as possible, stick with photoperiod fems in my opinion.
That way you can chose when to flower them and this guarantees a decent harvest for all your hard work and effort.
Cheers, Organoman.