I have the following materials available:
"Double Red Line" akadama
Beam Clay pumice
granite grit "M10" (from my horse arena)
Bonsai seives: 1/4 inch, 3/16 inch, 1/16 inch (window screen)
acadama: Virtually all the akadama will pass through the 1/4 screen. I can collect 3/16" and 1/16" sizes. Anything that passes through the 1/16" screen is fines and will be thrown away. I would estimate about half will go through the 3/16 seive, and half does not.
pumice: I can collect some that will not pass through a 1/4 seive. They're still relatively small, so I could possibly use this as a bottom, drainage, layer. Most of it will pass through the 1/4" seive, but get caught by the 3/16" seive. Maybe three quarters of the pumice will get caught. The remainder gets caught by the window screen (1/16). Very little is fines.
M10 (crushed quarry granite): I can collect all sizes.
As I understand it, the goal is to have a fairly uniform particle size. (Not including the bottom "drainage" layer.) So, I can create two sizes: One that will pass through a 1/4 inch seive but not a 3/16". And the other can pass through a 3/16" but not a window screen.
The larger of the two sizes seems fairly large! But I think it would be appropriate for pines.
The smaller of the two would be good for deciduous trees?
I am thinking of having 2 parts akadama, 2 parts pumice, and 1 part granite. If I can find it, I might toss in a little charcoal.
Am I on the right track?
(Back in the day, I used to use turface "right out of the bag", and added Nature's Helper.) I have access to better ingredients now.