Hello.
Took the X-Plane 11 MD-80 for a spin to test out the extended cloud distances.
Weirdly, I seemed to see cloud for a greater distance on the ground than in the air. A setting of around 15,000 sq km seemed to be about the maximum visibility I could achieve, setting it higher seemed to make the cloud coverage below the aircraft more dense and resulted in killing the frame rate. In SkyMaxx v3 if I upped the coverage settings the clouds became thinner around the aircraft but extended much further.
I did try setting X-Planes visibility settings to max but this didn't seem to help.