Those seem like good starting points to me. A big consideration for your mix though will be your watering practices. When you have more organics in your mix, you usually have to water less frequently. But, at the same time, you need to more closely monitor your trees to see when watering is needed.
For me, I'm using a 100% inorganic mix (using ingredients like pumice, lava, grit, haydite, and in some cases, akadama, with a bit of horticultural charcoal thrown in) for all my trees, except for my bald cypress. I have to water every day, but at the same time, concerns of overwatering are dramatically reduced.
Soil mixes involve a lot to think about. I started out using mixes that were 30% or so inorganic, and slowly phased out the organic components over time as I got more comfortable with my trees and watering practices. My trees seem to be growing better in my current mix, but it could also be that I'm a little more experienced now that when I started a few years ago. In any case, I would probably avoid expensive components like akadama at this time. Source local, cheaper components and see how things go. Over the next few seasons, you can experiment with different soil mixes and watering combinations and see what works best for your area and schedule