You mean only half your seeds sprouted? If so, that is just poor seeds and nothing to do with TRAINING plants.
Wee growth…yes, many auto’s will stunt and give tiny little plants (from stress at an early age) and go to flower with a couple / few weeks. I have had auto’s flower in as little as 2 weeks. When I do an auto run, I usually plant 12-20 of them…then selectively move the evidently healthy plants to larger containers and the others to 1 gal cloth containers…
The LIKE in auto is DIVERSITY and quick turnaround. I really like the many different strains I can grow at 1 time to have a more diverse stash and try different strains. I grow photo from “TIME TESTED” strains, my favs, and stick the auto’s in there to bloom in between veg / flower without having to wait 4-6 months for a harvest. Can’t do that with photo unless you flip at early stages and then you reduce the harvest anyway so might as well grow an auto…I like 6 weeks veg, 7-10 weeks flower.
You can push auto flower if you know how. Check out @Kronic to see how he passed 200 days on an auto. Using TRANSPLANT methods along with nutrient control, I Pushed GSC auto over 4 months…1gal to 3 to 5 to even 7 gal containers. Transplanting interrupts hormones due to the EXTRA ROOT SPACE the roots find and changes natural time settings that ruderalis normally go through.