While the question was directed towards member cjet69 I hope that you won't mind me adding some information about the ignition and coil testers. While I am more familiar with the Merc-O-Tronic units I believe the Graham testers worked similarly and yes they would perform tests that a good multimeter cannot do. The testers can actually fire the ignition coil in a points and condenser ignition set up out of circuit and display the spark being produced in a spark window so you can visually see it. You can also observe how much current it takes to make the coil produce a spark at the spark gap and compare it to a chart to determine if the current draw is in spec or high. They will also measure resistance down to 0.1 ohms or better which a lot of "good" multimeters may or may not be able to do accurately. The testers will also test a condenser under true ignition generated voltage levels (which can range up to 300+ volts for brief periods of time in the primary circuit) something a good multimeter usually cannot do since it relies on the internal battery voltage of the meter to measure the capacitance value of a condenser. A capacitor may measure the correct value at a lower voltage but break down and partially short out when exposed to 300 volts in which case a good multimeter may show a capacitor as ok when in reality it is bad and creating a misfire or making the engine perform poorly. These are just a few of the many things that the ignition coil / condenser tester can do accurately that cannot be done using a good multimeter.
