Mithras said:
If you have access to jTas early editions I believe this topic was covered in depth in one issue.
As for designing a triple regime shuttle craft I probably would go with a Tailsiting based design. From a operational point of view it is a solid reminder to pilots that they need to set with a reasonable relative air speed to the surface. It also allows for extendable buoyancy control in the form of extendable floodable tankage for trim control. It also places the center of gravity in a reasonable position.
