I was inspired by your article, so I have written 2 of the companies about a possible co-op for Daves Garden members. I also called the manufacturer of pro mix with biofungicide to ask if I could use Mycorrhizal products with that particular blend. They said yes for the endo, but weren't sure about the echto.
I use the ProMix BX which, I believe, already has endomycorrhizae in the mix. Adding ecto should not hurt anything, since many mycorrhizal blends contain species of both fungi. Keep me informed about the possible co-op.
Apparently, you get the biofungicide or the mycorrhizae in their blends. Troy recommended that I use the biofungicide when I have issues with rot - cuttings, seedlings, small transplants, then change over to the BX when potting up. They found some synergistic action between the biofungicide and the endo in their research.
I'll inform you first when I start the thread for interest.