Keith, I spent Hours upon hours trying to get scratches out of a Road Runner Rear Glass a few years back. Never really looked much better that when I started. I used specific glass rouge in different coarsenesses . I think the deal is, If you can feel it with a fingernail, it's a no go.
I don't even care if they are out completely. just not obvious. I read on a post where somebody got some out, but caused distortion. that would not matte rmuch unless it was really bad on a side window.