I have found it all comes down to the way you want to calibrate the engine, in short the more ign power you have (real delivered energy v's paper claim) the more flexibility you have to use all the tools at your disposal. I.E. Free ign timing setting, plug heat range, fuel mixture.

You are tuning the engine, not the lack of spark telling you how to tune it.

It's a balance to what you can afford, how it runs, how many plugs it chews through lol, how many CDI units melt in some cases too. I have found power losses ascribed to arbitrary things like ideal fuel mixtures etc don't take into account basics like ability to run much higher boost pressures (even on fuel alone) that more richness allows, its however not able to be exploited when you don't have the ability to initiate the combustion process.

The inner BDC in my typed that reply lol.