Store the box's dimensions in a single key, acting as (maxs-mins) which assumes the box's center is at the models origin. The box's center can be set up to be movable via "Origin" property and rotatable via "Angles" property.

If set, the semi-transparent box "walls" will not be drawn.

If set, gizmos will be shown in transform mode to quickly move/scale the box. For "dimensions" box Origin/Angles must be set.