Barry, one's experience, mine.
 
I own a Mirage 27' and after 8-9 years the plexiglass in the windows
turned milky. Mirage is out of business now. 
 
I decided to do my own and it was easy. I got a 4' by 8' sheet of LEXAN.
Note: LEXAN. It will not be affected by U-V at all. Will scratch just as
easy as Plexiglass though.
 
These panes are normally held in by an escutcheon (sp) that is just a
rubber tape, a little more than a tape. Have a look at yours and if you
see a small slit where the 2 ends meeet, you can pry it out. Get a new
one.
 
With the 4x8, I was able to do 5 other boats and everyone is happy. I
recoup my cost too.
 
That sheet will run you +/- $85.00 or get some left over portions. 
 
Good luck.
 
- QWKie v3.1 - 
--- Maximus/2 3.00
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