FWIW, the few 825 all original [AFAIK] adjustable vent cabs I've seen with a 'grill cloth' actually had cheap steel cloth stretched/stapled to the baffle board cleats and apparently sprayed along with the cab which lines up with the drawing, so what I used for my clones. I couldn't find any in a quick search though: http://www.lansingheritage.org/image...ure/page09.jpg

GM