You are doing a fine job. When adding nutrients, I follow the 911 rule. Watering very gently and slowly in the center of the pot until 10% of the water I used comes out in runoff, then I check the TDS of the runoff. If it's above 1100, I leave it alone, but if it's below 900, I give it the recommended dose of nutrients for the given age of the plant. It has worked every time for me. If any water goes down along the sides, the TDS will be lower than it actually is.
I would recommend transplanting twice, maybe use 8oz(225ml or so) capacity pots for seedlings, then goto 1 Gallon(about 4 liter) pots for vegging, then transplant to 5-10 gallon pots (20-40 liter) pots a few weeks before flower. I use progressively stronger soil mixes at each transplant (100% happy frog for seedlings, 50/50 Happy frog/Ocean Forest for 1 ga with pumice, charcoal, worm castings, kelp meal and neem seed meal, then 100% ocean forest with the other amendments for flower) and slightly starve the plant before each successive transplanting so the roots "pop" into place.
This is what works for me and is just one of many ways, finding out which works for you is part of the fun budy.