I used the levels suggested by Phyter, and I did not change them during the process..
Here is the advice Phyter gave me. I used the ~1 gram/liter throughout the grow.
"We use 1gram into 1 litre of water. You can use up to 5-10 grams this way as application on the Roots. Get a good sprench going. The spores become active in the water, and will need to find a host to attach to within 4 hours. So, into soil, they'll look for the roots, or the seed shell, anything that can sustain.
I imagine you will all have scales, making the measurements easy, but if not, it's about a teaspoon into that amount of water. Keep good agitation. The powder is heavier than water and will sink. So if you are using a backback sprayer, or little bottle, just keep shaking it to suspend the spores in the liquid."
As I recall, I made about a liter each time I applied, and that was used on the four plants, all of which were on the small or smaller side. I doubt that the exact concentration is that important, what really counts is making sure that all flowers are inoculated early so the the bennies are well established throughout the colas before they get vulnerable. Just my thinking though.