it was autoflower.net i used as research for when i was growing my auto's, its pretty much a general consensus round there. i think ur pretty much agreeing with me anyway, i've said that the growth u get from 24/0 isn't worth it, probably down to the roots, as you suggested.
have you grown a lot of auto's? spoken to a lot of people who have?
i'm not saying my word is final by any means but there is an entire forum of people dedicated to growing autos that'll say similar to me based on their experiences too