Sounds like we're on the same page, im still wet behind the ears, you're probably further along the page than me

I believe he said he got the mix from Cornell maybe? I think he tweeked it a little, but haven't really done more than a quick Google search on the subject.
What goes into your soil mix? I always like hearing what others use, never hurts to have a little more knowledge. I guess that's one good thing about us tokers, we burn enough brain cells that we get to learn things 2 or 3 times

I would answer, the best I can, by saying university extensions have taught and understood not only soil design but everything about horticulture for decades. Farming sciences are quite advanced too.
While cannabis is currently a high cash value crop due to legal issues and regulation, its far from the most valuable crop in the world.
So this is just to say that Coots is a great starting point. He says in his blog he started this about 10 years ago, after doing other horticultural work.
He is a good teacher, and that counts for a lot. However, I am only saying this...not to dis Coots, just to help guide towards a broader set of guidelines than just him.
I would take a half dozen of the advanced growers here, and their opinions over Coots. They have more experience and are not "guessing" at what works, or guessing at why. Many have actual degrees in these sciences. They dont always speak up, because they get annoyed trying to correct what is often called "broscience".
Again, his mix is excellent, no issues. Mine is similar -- because a good mix uses a similar 1/3 1/3 1/3 mix of some sort. That concept, how to build it, is a much more generalized how to build a quality soil exercise than the "optimum soil".
My best advice is do not overcomplicate it. What goes into the compost portion of the mix IS critical, but not the exact mix. Quality is the key. Really high quality worm castings, for instance, are more valuable than whether or not you added alfalfa or what form of neem meal is chosen.