Spark plug reading

I consider leak down values within 10% of each other very good. There are many reasons for cylinders to show different leakage including variation in ring location and alignment which can change over time. The most important thing to listen for is valve leakage and then head gasket leakage. I wish there were a way to pressurize the intake manifold to check for intake gasket leaks, but I haven't found a good way to do that yet.