We top dress and we don't use a hot layer. One soil but I have lighter seedling mix for beans. Clones and everything else get regular. It's made to be easy, cost effective, friendly to the environment, less labor and most important produces the finest quality medicine ever!! Yeah I've done the Sub Super Soil thing and it works for some strains but others it will burn. This kind of soil will work for all from veg through bloom over and over and over....
Only my pictures will prove I guess as time goes on