I think you should
1. figure out what you have
2. if it is correctly put together before you go buying a bunch of stuff sticking it in and further confusing yourself.
TO start
do you have a factory manual and
a WIRING DIAGRAM ??
What is factory design?
IS factory design what you have?
do you have an alternator or a generator?
Do you have 3 cells (6 volt) or six cells in battery (12 volt).
IF 12 VDC then you need to figure out coil circuit. These came in two flavors
12 VDC coil and a 6 VDC coil with a dropping resistor. Resistor was bypassed during cranking to deliver hotter spark. During run resistor was in circuit so coil ran at 6 VDC.
Dan Bentler