Yes, I'am aware of that, it can be even something close to a straight line, but what I'd like to know is, where a model have to be, on that 10" line, to be counted for the scheme.
I know that distance between the points a asked about is small, but sometimes this can be the difference between having a point or not.
Because if we put two markers, precisely 10" form each other, and we assume that the field of scoring is counted from the most left/right point of the marker (the way we draw LoS), then that line will be longer by about 1,5"