There's tools that can measure them. A low end is just a piece of metal that fits the edge with no light coming through. You can use a true bar and look with a

There's tools that can measure them. A low end is just a piece of metal that fits the edge with no light coming through. You can use a true bar and look with a loop or magnifying glass. Check out this tool: https://www.sidecut.com/product/BEBM.html?Category_Code=base-repair-tools https://www.sidecut.com/product/BEBM.html?Category_Code=base... It's ridiculous how much you can spend on tuning gear.