What's up Hombre?
For seedlings and newly rooted clones I use 1 part Super soil and 3 parts potting soil, or 1/4 strength Super soil mix. Or you can fill the bottom half of your pot with Super soil, then fill the rest in with the potting soil. The main thing is not to let the roots touch the super soil when you transplant, you want a little "buffer" so the roots can get use to the hot soil mix. Earthworm castings are great for seedlings and clones also. I've never used any of the Fox Farm stuff, but a buddy of mine does and loves it. He gets good results too. It's just to pricey for me, I can't see buying bags and bags of soil for every grow. Funny you're switching over to soil and I'm switching over to hydro. Well I'm gonna keep 1 soil plant just for me and the wife, probably a sativa. Going 4 DWC moms with 4 2'x3' Ebb & Flow tables. Let me know what you decide to do and how it works out for you.
What's up Hombre?