Coots works well, but he highly emphasizes that it needs a high quality worm casting/compost input. It needs strong microbiology to get those slow release inputs available.
Personally I have been using Ph-Patrols, rich as fart mix recently. He also recommends high quality compost input. I like this mix a lot, I have used Coots, and I have used Tom Hills mix, and many many other creations.
Really there are a large handful of nice soil mix's laying around here waiting to be tried out. Could choose one that you can get the ingredients some what locally and easily, and also that fits your budget. Splurge on the castings/compost.
I would emphasize, using good compost in it also. Good microbiology from the start and the rest is downhill.
Bagged soil, is not bad for a percent of a mix. I would not go straight bagged though, you will end up needing to feed tons and the microbiology will poor. Also there is randomness in the big bagged soil companies. There batch's are typically uniform but you never know really.
Sounds like a nice seed line up, and 100 gallon pots will be killer. February is very early to pop seeds. Even in 1,000 gallon pots, I think February is to early. Mid/Late March should be plenty early enough if you are on the northern hemisphere.
GL and HF,