Never grew Auto flowering strains, couple questions

i want to have a couple auto grow plant next summer for my outdoor and was wondering how long do i keep them under a light for before i put them outside. and i have fox farms nutrients should i just use half of what i use for my photoperiod plants? thx

every time i have done them outdoors i just put em in the dirty (no germing) outdoors and let them do there thing til its time to feed them with stuff

i could just do that but would i get bigger plants if i start them off under 24 hour light or will it stress them when i put them outside

I let mine run indoors under 18/6 for 2-3 weeks then put them out...

My first auto's season; Sprout, no problem, pops up out of soil, stalls & dies. Two suppliers. Seedlings placed in Mondi propagator on a seedling heat mat left in a shady spot till true leaves appear then progressively more direct sun. Works fine for my photo period plants. Best auto was 16" tall at harvest BFD! What can be shocking them to death? (So. Cal.) so temps should be fine, especially with the heat mat keeping soil temp up at night. Checked and adjusted several times a day for moisture/temp/exposure. Two of twenty made it to harvest and then hardly worth it. Does that putting seed directly into final container at sprout really work? These seem SO finicky and weak. I think combo of weak seeds and something else???? Never wasted so much time growing before for such a little result. Only done to help bolster a season delayed by weak poor photo period seeds of which only one in ten made it to harvest (though it's a beauty). Any ideas what I'm doing wrong? Does the outdoor sprout really work??