Is this mix good for Junipers?

[Fairfield Scott]

Hello, this is my first post. I'm not new to gardening, soils or horticulture, but I'm relatively inexperienced with Bonsai. I'm aware of the concepts of porosity, field capacity, etc.... I created the following mix: 1) 60 percent pumice. "Dry Stall" was the source. 2) 20 percent calcined montmorillonite clay. EP minerals "Safe T Sorb" was the source. 3) 20 percent crushed granite. Manna Pro Poultry Grit was the source. Everything was screened to 3-6mm. I also tested for Phi, AFP, WHC and Saturation. My numbers were 57.5 percent, 37.5 percent, 20 percent and 34.8 percent respectively, which from what I've seen here is close to Boon's Mix. What if any drawbacks or benefits will I see with this mix for Junipers?

 

[Brian Van Fleet]

Probably ok, will likely require very frequent watering. Pumice is very dry and grit doesn’t absorb much water; just adds weight.