Further explaining the issue with the Earth size. I basically create a flat plane in the cylinder map in order to preserve the circular shape (you can see that issue with the images I posted before). However the center of the planet is closer to the camera, meaning the pixels in there are zoomed. If I try to use a spherical object in order to compensate for this distortion, the shape is too visible on the pixels near the corners:
An alternative is to use a new image with the shape corrected:
But then it stops using the original art.