68 SS Door glass or lexan ? your idea ?
There are places that can remove scratches in glass by basically milling/machining it. I think thier key application is high rise buildings. I wonder if they could mill/machine/polish an original thick set down to "thin" thickness.
I know ns1rm21 bought a set of Brazilian? repro side glass that was about 25% thinner. It was cheap too. But that was for a Dart.
$4K for thinner side glass, I'd think about how spot-on accurate to a race time period or theme the car was to justify that.
Unless you are racing it, I don't see bothering with Lexan. They were not Lexan at all originally. More inaccurate than thick stock glass you have now.