If the points aren't opening, that is why you don't have any spark.
Start from scratch on the ignition system - new points and condenser, known good cap and rotor and wires. Adjust the points per the specs in the Shop Manual.
Has anything been done to the starter? Does it need a rebuild? The 6 volt starters will turn noticeably slower if the bushings are worn and the rotor is dragging on the field coils. How are the brushes?
A big issue on six volt cars is battery cable size. The skinny cables meant for 12 volt cars won't cut it on a 6 volt car. Do a search on the forum, there are a number of threads on 6 volt cable size. A good website and source for cables and fittings is
www.custombatterycables.com, check them out. Here is what they say about 6 volt battery cable size in their FAQs:
What do you recommend for 6 volt electrical systems?
Six Volt systems take twice as much current to do the same work as 12V systems (Power = Voltage x Current). The battery cables should be sized to handle that increased current. I'd use 2/0. You can't go wrong with that and it does not cost much more than 1/0. I would not go any smaller than 1/0. A lot of people move the positive battery cable connection (where it attaches to the engine) down to a starter bolt. Again, if you search on this forum you should find discussion on that.
Personally, I would get it starting/running correctly with the points, and then consider a electronic module. Don't throw another variable in the mix. Others may disagree, just my opinion.
Keep us informed of your progress.