If you are looking for actual ampeg B-15 schematics and dimensions they are all over the web. I'll go hunt and post some links.
click on the schematics link and scroll down to the year you want.
http://www.unofficialampeg.com/
http://www.unofficialampeg.com/schematics/b-15-n68.gif
http://www.vintage-blue.us/tb/tray1.jpg
Here is a tribute page to all things jess and portaflex
http://images.search.yahoo.com/images/v ... vBjwn6behI