Okay, I'm wanting to make an end grain cutting board, however, our local stores don't stock anything thicker than 4/4 except in Red Oak which is not only too porous probably but also way over used in contemporary times by my mind. So, I'm looking at the possibility of using 4/4 boards, however, this will limit my cutting board thickness, or is it the squares dimension that it will limit? Oh damn it, every time I've decided that answer a is right, answer b looks right. This is why I wouldn't be a good mechanical engineer I guess. Thanks guys, I'm a fool!