you can use the later G100 electronic coil if you want. Its not very long life though, you can also choose to use a regular black ND oil filled oil - make sure that the primary windings are not very low impedance - if it is then use a resistor on the primary side, check that you have a hot start wire direct from the self starter to the coil directly (resistor bypass) to get good spark for quick starts.
Its a pretty simple job, choose your brand there are quite a few, ND, New Era, Mitsuba, Hitachi, Bosch, Siemens, Hella, Delco. Get a good NEW one, dont rely on scrap yard coils.