Need advice on plastic rear window

[fullthrottle52]

My rear plastic window is pretty pliable yet but has the normal wear areas and scratches. It is the original so it is 12 years old. I just received the 3 step restoring kit from NOVUS. I would like advise from others that have used this product. Many on this site highly recommend it. My concern it that this product is for all plastics, including plexiglass. Our rear windows are pretty soft vinyl so I am worried about taking off to much with the #3 polish. Has anyone uses an orbital polisher on their window to get the deep scratches out?

Any comments and experience would be appreciated.