Single, double pane window glass\lexan?

[orozcom]

1774 31 ft Sovereign Land Yacht.

I have double pane windows, but it looks like a combination of glass and I don't know what the inner part is? Lexan, Plexi, etc... I have a few questions.

1. Is the inner glass curved like the outer window?
2. What is it?
3. Would it be better to just convert to single pane?
If I convert to single pane, how do you fit the single glass in the frame? Do you need some sort of special trim or gasket?
4. If I stay with double pane, can you get new inner lexan and have it cut to the size you need from the old inner window frame, or plexi glass?
5. Is it better to have two glass windows vs glass and lexan?
6. Tint - I was thinking of tinting the windows. I guess if I do that I should have the inside of the exterior glass pane tinted? Or should it be the exterior?

Michael