Here is some service info to keep the Dixie Aero alive and well. They are a different beast. Be wary of very fragile pot metal. The magnets are mounted sideways unlike most and must be charged as such. Before a frontal assault this info may prove useful.
The process described above is how one can check the edge gap. That is, the optimal time to open the points to get the biggest bang at the coil relative to the position of the rotor that conducts the magnetic field through the coil.
Grinding the rubbing block is a good quick way to destroy a scarce part and downright crude in our opinion. Some mechanics back in the day merely pulled the cam, renoved the key from the keyway, reinstalled the cam, rotated it to the optimal edge gap timing and tightened the retaining screw. This is probably a better idea than chewing into the rubbing block to giter done. Issues here often explain why when the coil is hot, magnets charged, points clean and set, condenser good,and all connections sound yet a wimpy spark.
This test is dangerous and not valid. It will not test properly for electrical leakage or shorts and is a good way to get electrocuted. Whenever working with live electrical circuits always keep one hand in a back pocket and stand on a plastic non conductive mat. Moral of the story: Don't do it!! Always safety first. We have seen testers with two probes. Holding one probe in each hand creates a straight path for electricity through your arms and heart capable of causing a fatal cardiac arrest. A shorted or leaky condenser will show a false positive test here. Best to use an actual automotive condenser tester, not a digital capacitor tester as they do not test for leakage which is probably the most common cause of condenser failures.
These magnets do not charge like most. They are mounted the wrong way for mist charging devices.