Great looking car! The chop would really make it look sinister, are you sure you want to go 4 inches? That's a bunch! One way to do the back glass is to cut it our completely, then put the whole thing back in laid down as you mentioned. For the windshield you could recess it into the firewall then build a false cowl above it to finish it off. That way you can easily replace it with a stoick one if it is ever damaged.

Some of the guys here are real talented with photoshop if you want some ideas on how it would look modified.

Have fun with it and welcome to CHR

Pat