Can you get an LM1815 where you are? It's a nice chip for reading inductive sensors, and would simplify the design.
Running 2 coils in waste spark, or individual coils would be simplest.
After that, it's all timers, math, and an ignition lookup table. If you want this this to be tricky or have a course trigger resolution, you can try to adapt to changing engine speeds. If the engine speed is accelerating, you'll need to reduce the timing accordingly to hit the correct degree mark and vice versa.