Hi All
Knew this question sounded familiar here are photos of one design of the sliding plates in the from a previous discussion of what they look like and what are the dimensions.
Pattern 13 Rear Cab Sliding Window
Page is slow loading because the picture files are large, pictures with ruler of the sliding plates are the third or forth item down under the heading Pattern 13 Rear Cab Sliding Window.
This is a page on my web site that I use to answer questions by giving people a link to specific photos.
Cheers Phil