i start my seeds directly in the soil (appx half inch below surface) in the "#1" pots (aka 1gal) and that's where they grow until sexed. then the females are transplanted into the "#5" (aka 5 gal) pots where they finish 4-5 months after the seed was planted and the pots are always rootbound to the point i wonder what happened to all the soil sometimes...lol

and yes, super-thrive was made for transplanting and reduces shock. there are cheaper alternatives to be found that work well enough but i rarely have probs from transplanting when i give the plant a good dose of s-t solution a couple days before the transplant and a heavier dose in the pot just before the plant is moved into it (on top of the soil of the soil in the half-filled pot) and another right after getting topped off with soil when the transplant is finished. same regimen works well for me when moving clones from the rooting chamber into potted soil (but i use smaller pots and won't transplant again (into the #5's as they have already been sexed) until their seedling starter pots are rootbound.

HTH...