I don't typically use pantographs that have reference marks. What you have to do is look at your pantograph and usually there is a portion on the top from the row before that is maybe in dashed lines. measure the distance between that dotted row and the full row in solid line below. Hope this makes sense but usually it's about maybe 1/4" in between rows and you have to just use the number you find with that measurement. I hope this makes sense, otherwise let me know and I will try to clear it up.