I am trying a new (for me) mix for the 4" and qt pots. I go from the peat pellet up to 4". Some of those go on to qts. Then there's another group in the 2.5 qts. I usually use Miracle Grow potting mix as it is easy, and for the most part works. Also in the chillier months work much of this out of the kitchen so don't need lots of mixing and all.
As MG can get a bit heavy, as well as the Fafards I've been trying, am trying to mix in some Black Kow. The Kow is aged poo with very low numbers, and some sand and other stuff. I figure mixing it in with the grainy texture may help the heaviness of the bagged stuff.
I'll try to let you know if the plant babies keel over, just go whatever or grow as if on steroids. Hopefully just go on their own way, a bit faster growing wouldn't hurt, and the mix should have better drainage.