stop right there. Haven't read all of the posts but don't go dropping 500$ on a new window.
I have had deep scratches on my last pickup's cap windows. Found out that 3M made material to polish and repair glass (example:
Glass Scratch Repair Kit 3M Trizact)
Be prepared though, it will take you a few hours for sure. It is a long process, and you shall
absolutly follow the instructions given with the kit.
What I did buy to do the job is a 3M glass repair kit, plus some coarser disks to customise the kit for the job.
The worst that could happen if you do not have enough skill to to this, is you lose the approx. 50-75$ your kit will cost you.
PM me if you want details, as I did the job 1.5 years ago, I still remember some of the details.
you can polish out deep scratches from glass. You have to use the right material and polishing compound (which is now way the same thing as sanding paper for metal), the right technique in blending the depth of the scratch around.