Just a couple of clarifications on this sparkplug issue ..........again.
Platinum sparkplugs are used, primarily because of reduced electrode erosion !
That's why most newer vehicles have them ( since so many OEM's are playing the stupid " no tune-up required for 100 k miles" game ).
Great..........you try to get them out after 100 k miles, especially with aluminum heads.
As for multiple ground electrodes, my W 202 Kompressor uses Bosch F7 KTRC, with the "T" standing for triple electrodes.