I have a recessed board for copal 0. Lemme think about letting it go. In the meantime, there's a chap on ebay that makes them for cheap. I just had him make a 163mm square for my Cambo that accepts 4x4 boards from my Calumet cc-400. It cost me less than $30 plus shipping to have it made. It works very well, and quality is fair.
BTW: the big kid in my avatar is my hero, my son, who proudly serves us in the Navy. "SALUTE"