I'm not an expert on anything and pretty inexperienced myself, but I would focus on sourcing the best quality compost you can find for getting the soil started. I think getting a quality compost/ewc source will put you on a path to where it'll be harder to mess up than it will be to succeed more so than any specific tea/amendment will be able to provide. The compost will provide nutrition and fresh microbes back to the soil however you choose to apply it, tea or topdress. If you can grab some good compost or ewc, it seems like there are a lot of viable dry mix options you could grab for down the road before you flip to flower. I have never used or really looked into either of the soils you linked, but I'm sure they have plenty of nutrients built up in the to keep the plants going for a while. A well rounded dry mix/compost topdress would probably be "safer" and easier to apply than a tea or you could even source a few single ingredient amendments for now and also for future amending after this first grow.
I'm not sure where you are located, but I found a local hydro shop that carries a wide variety of Build A Soil products now, so I luckily have access to the composts they use/used if ever needed (oly fish mountain and malibu composts). Also found a hardware store that will ship Coast of Maine composts to their store for free and be be able to pick up in-store several days after placing the order. I'm sure there are plenty of other quality commercial brands out there as well, but I have read good things about these three specifically (used a bag of Bu Malibu compost and thought it looked/felt/smelled great and would use again, just a bit pricey).
Sorry for the ramble, just my two cents. Good luck moving forward though.