Nice to see another growing looking into the Auto's.. once you get them dialed in they truly are a wonderful thing harvesting every 70 days.. The worst thing you can do though is start them in the small solo cups.. it stunts the tap root and they just never recover.. Now I know people say to start them in the pot they'll finish in but I find this to not necessarily be true for me.. I don't care to waste soil and time, I start mine in 1gal pots because when your starting 12-15 plants it's difficult to start them all in larger pots.. I use 1gal nursery pots until they show sex, some show in 7 days some in 21.. the longer they take to show sex the larger the plant is my rule of thumb... so if I get a lot of females I keep the ones that take longest to show, especially when making more seeds.
Once they show sex, right into 3gal pots and within 2wks they've almost tripled in size.. but please stay away from the solo cups.. Auto's just don't like them.. I wish you the best of luck man.