mmmm cream puff.
Ever heard of the hi performance ignition systems used in the aftermarket car industry. Its called MSD do you know why its called that. It multiply spark discharge. Its used to simulate a magneto.
I would have you have a look at the LAME syllabus and do some reading. A magneto has a multiply spark.
Ok the second ignition system is totally independent of each other, and propagates a more compete burn and a more even burn across the piston head. Also a redundant system which is it primary use.
Next thing is also is the mixture in the burn the leaner the mixture the slower the burn, the richer the mixture the faster the burn.
Basic LAME training.
As for breaking a plug well you can break any thing if you wish but you can also not break any thing. It would seam you possibly no more than your LAME may be you should change your profession ?
There are no one answer for any problem the rules are not always universal for any aircraft.
Cheers