Good article Doc. Oly get an inexpensive but good brand vacuum gauge as it is the only way to adjust the carburetor. The tach you have is OK because you really only need it to set the idle and choke speeds. A MITYVAC pump is very helpful testing vacuum operated components. My MITYVAC has a gauge but it is not as sensitive as a proper one. Cranking an engine without it starting is rough on the best battery in the world. That is why I pull the plugs and time it that way, no strain, and you get the timing dead on.