I may have learned why cobra grain is the most-used replacement material: in considering other pattern materials only the cobra grain seems to be wide enough for my Series 80 top. The top is widest at the rear of the doors (2-door coach), plus the top rounds over each side and must fit from gutter to gutter. Any experience with the Series 80 top interests me as I am an amateur.
UPDATE: I was able to discuss with Eric Hartz at Hershey; he showed me several samples of materials which are available in suitable width for the Series 80 closed car. I think the appropriate material is available from him if needed.