This has been a very thought provoking thread.  Duo, your image is probably about as close to the feel one can effect for your client.  Your project caused me to stay up too late last night trying to achieve the effect.  

I was experimenting with multiple huge terrains, camera settings, and a different twist of placing camera inside and outside glass spheres with varying refraction settings to warp the view.  My 'puter crashed about midnight and I gave up.  I never achieved a satisfactory "feel"

During the thought process, I wondered about the enigmas of the Dyson sphere.  Maybe someone here would like to tackle these questions.

If the sphere was large enough to encompass a light source (mini star),  over geological time time, would the environment become too hot to exist?  Mega greenhouse effect.  Or would the heat be transmitted into space through the shell?  Would drilling a well encounter colder and colder ground temperatures instead of hotter?

Assuming pseudo  gravity could not be assimilated by centrifugal force like a ring world, the thickness of the sphere would have to be enough to have real gravity attraction.  ???

If the world was an artificial construct, shading panels around the sun would have to be used to create night/day cycle.  Without the cycle the atmosphere would be stagnant and no weather patterns from heating/cooling process.  Right???

Back on subject.  I think Duo is correct in assumption that any ground level view would be perceived as flat and a  viewer would have to approach the limits of the atmosphere to see anything unusual.