"You also create a condition where you have a bunch of coils that are energized all the time and will all spark simultaneously the moment the ignition circuit is cut.
On top of this, wouldn't coil overheating be a concern?"

Naw. You're just overthinking it like I did earlier. All I meant was that the on/off signal for the stock, single coil would be rotated through the 8 coils in sequence. None of them would be on until the transistor was switched on by the redirected EST signal. This would be plenty of charge time for a coil running 12.5% as much as the original coil. This is the basis of my non-processor approach to the problem. Just GATE the signals to the right coils at the right time. No calculation. No changes. Just sequence the gating so that it "arms" the right coil transistor at the right time. I have no intentions of going beyond this. You have plans to do so, I bet, and there's nothing wrong with running 2 arduinos to accomplish what you need to do. One to calculate, one to act on it. 2 arduino pro minis don't take up much space. (5v-16mhz versions) I don't know for sure if it would be fast enough, but at $5 each, it would be nice.

I have weekends off from work, and away from the best scopes. I have only 1 old 4 channel Interro PDA scope with a small black/white lcd display. Probably have to take a picture with my phone to get a decent capture. Or.....I could try for the next work week when I have access to everything. Either way, I will see what I can do.