Quote - So more like four minutes???

In that case you could build substantially more complex panoramas within a very very reasonable time!

I suppose it could perhaps, potentially be controlled by a Python script from within Poser too, which could send coordinates of your scene's "sun" light position in the sky, relative to the envsphere... would this be possible?

But I guess it all depends on how long building the custom render engine would take you to do?

How cool would that be. Set up the Sun /lighting where you want then make the sky to match, including the angle of the camera. Then pop it onto the sphere. How realistic is that though?