... Of course the ULTIMATE plug would be a surface gap one .....
Do they still make those things. They worked pretty miserably in anything I ever saw them in. '70s Kawasakis, specifically. They always struck me that they were too cold. The Kwackers ran much better on conventional plugs.
The reason airplanes use dual electrode plugs is because the comparatively low voltage of the circa 1920 magneto ignition. They won't knock off minor soot-type fouling, so they have to bypass it...hopefully. Any modern EFI ignition supplies much more voltage that can blow past minor fouling attempts in the cylinder.
P.Schraub...Haven't you ever had to clear a fouled plug in your Cessna One-Filthy?
Bare