jj,
I see you are in Sacramento...Any chance you are a member of the Capital A'S or a club close to it?
If so you can find the the deminsions for the rear quarter window (A-56780) of a 1928 Tudor Sedan in the FORD Service Bulletins on page 250. Also you can run down to Sacramento Vintage Ford and get the book.
But if not, the deminsion is 30-19/32 to 30-21/32 by 16-5/16 to 16-3/8 with 1/8 R corners and rounded and polished to a 45 degree angle...glass thickness is 5/32 to 9/32.
Steve Plucker (1992 Capital A's President)