Welcome back Joncoh. Good to see you are still around.
Neagari is the exposed-root bonsai style: Imagine a tree growing along a river, and the river over time erodes the soil around the roots. You get a tree sitting on every growing root-stalks. Especially with Azaleas this style is used.
I have heard of the high container type growing. As I have never done this, I cannot be of much help. I imagine you would have to support the tree during the first years as roots are not normally strong; In order to speed up the development, I would probably have a frame in which the tree itself is supported, in combination with the wooden box you described.