I can't help you, but thanks for asking.
Users of G-Clarons regularly report that their lenses cover much more than Schneider claims. Schneider claims that the 355 G-Claron covers 444 mm at f/22. 14x17 fits in a 560 mm circle, 12x20 in a 590 mm circle. I'd like to see the shots so I can decide for myself whether Schneider is as conservative as users say.