If any one is curious, my soil mix for these 7 gallon fabric pots ended up being:
1/8 organic bagged garden soil
1/8 black kow compost
1/8 coco coir
1/8 vermiculite
1/2 perlite
Amendments for each bag:
4 cups earthworm castings
4 cups biochar
2 cups dolomitic lime
2 cups greensand
1 cup kelp...