Well i dont know much about autos but i know that its best to use mh for vegging and hps for flowering but hps can be used for vegging also .
iv been using metal haldies for 1 month and 3 weeks and its starting to get some nice buds on itt but im switching to 12/12 for all of them which i know i shouldnt do it but i had an auto out of the bunch of my photos i have vegging and there aall being switched soon
Maybe try HPS plus some daylight CFLs for the first week or two, and then cut the daylight CFLs after that? That's probably how I'd go about it if I only had one ballast.
All I use is HPS and autos like it Have a look!! http://forum.grasscity.com/indoor-grow-journals/716779-stealth-diesel-ryder-autofem-grow.html