Also, I would really like to get personal experiences and views of what works and what doesnt... there are a bunch of very experienced people here and would be great to hear and learn from their experince, rather than read a list of soil mixes without understanding the context...
thanks again all..
Have you visited the page Clicio suggested? Because there I actually went beyond the scope of a specific mix, and basically put down the requirements of a good mixture.
In the end, you have to use what works for you, and the tree really does not care much, as long as your care and the substrate are in balance. Trees can cope with loads of substrates. Fine roots are only a concern once you have the basic tree in place. I have both trees in the ground (sand with organics, no grains > 1,,) as well as in pots, in my regular substrate mixture -find that in the link that Clicio posted-.
You need to ensure the roots do not drown (=lack of oxygen). And you need to ensure the roots do not dry out (=lack of water) and you need to ensure the roots have regular access to nutrients. If you meet these requirements, you are half way home. Ground growing is more effective, because plants are "aware" of the container they are in. In full ground, they grow a lot quicker.