Hello

Im trying to create a panoramic image to be used as an environment map. I took 9 portrait photos with plenty of ground and sky. Ive stitched these in photoshop but im having trouble mapping the image to a sphere. Is there a certain approach to creating the right spatial dimensions for a panoramic image. I dont have a fish eye lens so my panoramic is about 5:1. I don't have a chrome ball either.

appreciate any advice on topic
thanks
JIm