Spark plug grade

[Bison]

Hello folks,
I read on the Dutch Morini site they recomend using BP6ES plugs rather than BP7ES, anyone have any comments?.
While I'm asking, does anyone actually know why a wasted spark ignition system burns holes in pistons?. Yes, I know it's because the temperature in the combustion chamber is too high, detonation, weak mixture, too much ignition advance etc, but why on a wasted spark system and not any other?. Is it usually the front or rear piston that holes and just how often does it happen?. Is it all wasted spark systems that cause this or just the brand I read about?.
Thanks,
Alan.

[EVguru]

I've been running BP7ES plugs in my 350 Sport for nearly 10 years now. They've been working just fine.

The wasted spark issue....

Ignition systems that use a dual output coil or fire two coils at the same time; The front cylinder spark also appears on the rear cylinder. The wasted spark on the front cylinder also appears on the rear cylinder. The reverse is also true.

[Bison]

Hi Paul,
I'll change back to BP7ES plugs then.
Yea, I understand the way the wasted spark works, just couldn't figure out why it would cause the combustion chamber temps to get so high it would burn a hole in a piston, assuming the ignition timing wasn't too far advanced and the mixture wasn't too lean?

Alan.