I have sold and fitted hundreds of them.
Works perfectly on all K series with magneto coils, takes about as long to fit as to fit points and a condenser, once it is fitted just forget about it. Engine will start easier and run smoother. When I go out to non starters I do not waste a micro second on points and condenser, I automatically change to electronic ignition.
The issue that I have is with the poor quality of the points that are being manufactured today, watch the moving side of the points floating about whilst you are trying to set the ignition timing.
The module does not vary the ignition timing, it senses peak voltage in the magneto coil generated by the fixed flywheel magnets then triggers ignition. If you put a strobe timing light in the circuit you will see that the timing is dead on at all rpm.
The Mighty Atom modules that where developed and made in Australia have not been about for sometime, they worked on similar principles to the one I sell.
By the way the picture is copy righted.