I do not see where the mat'l the scale is made of makes any difference. it should not be placed parallel to anything. It should lay perpendicular to one direction of the checkering. I did at one point in my life have an old .41 rimfire Swiss Vetterli rifle which had a coarse square checkering. In this case you would have laid the scale perpendicular to one line of the checkering & it would have been parallel to the other. You measure on the perpendicular though & with a Diamond pattern you're not parallel to either set of rows.
