Crank Sensor

I see the reference tooth, the falling looks to be where the rising edge would be for normal tooth. The early rise is detected by comparing to normal gaps.

I think can make that signal with micro, and looking at flex plate signal an a single reference tab on distributor. You would need to add that tab and sensor. Adding to one end of advance slot limit plate. There is a Mallory, I think that has a dual trigger distributor with reference and 8 trigger. I think it costs more than you want to spend, then more $ for electronic advance ECU. Makes MS look cheap.

I see a bunch of work, little gain by trying to use mechanical distributor. It might be easier to piggy back and alter timing signals on the OEM system with micro. Or find a way to alter OEM timing tables. I doubt tuners or chips are available.