Ok. Follow up time. The whole thing got out of hand. I initially intended to do up a 15-20 gallon pot to make it through a run water only. Now I have 2 65 gallon grass roots pots cooking with a coots style soil. I think I just have a spending problem. Hopefully, such a mass of soil should make nutrient issues a non-issue, at least.
I want to add that I mixed the soil, very thoroughly, in my living room, in storage totes. I'm sure it would have been much, much easier if I could have done it outside.
The only thing I would suggest is having liquid nutes on hand, even if its teas of some sort. Any nutrient issues that you need to amend will take a few weeks to show change in the plants if you use powders.