I am in the process of getting a quote on having the gasket material made for the W42 windows to the same dimensions as the original one used. Since there are some minimum amount requirements to have the gasket material extruded, if there are any other W42 owners thinking about replacing the window gaskets, let me know.
The original is 13/16" wide, by 1/2" high. There is a notch in it that is 3/8" wide by 1/4" deep to accept the window..