My old filter had gotten dirty faster than I'd expected, and I needed a new one right away. They sent me one in just a couple of days! And it is a non-standard size that I have not been able to find anywhere else.
Filters were just a tad oversized. Not sure if that is my measuring mistake or your manufacturing error. I managed to squeeze the filter into the available space without too much of a problem. I think I will reduce the size by 1/4" the next time to allow for any extra that results from filter assembly within the container web.