Ron,
I'ld say you would have to throw (atleast) two more variables in this mix:
How much time do you have to water? Vs. How much of a "conveinience mix", if the need be, can the tree handle?
I only have three trees, and a small jade in a 4 inch oval pot (just for kicks). So I don't mind spending fifteen minutes per tree analyzing moisture levels and watering. My situation let's me use very quick draining, high maintenance soil. But most growers have tons of trees, I'ld imagine that most of the trees would get a mass watering with a hose. Except for a special few who would get individual treatment. I'ld imagine these guys would be tempted to use the max. moisture holding ability up to what the roots would stand for. Especially true if they give each and every tree it sown personal soaking each day.
The four questions would need to be used in proportion to each other.
I don't think I answered a thing

jim