Henry,
I'll do my best he
Henry,
I'll do my best here to answer your questions...
If the plug gap is too spark, you risk pre-ignition...the spark occurs too "early" in the combustion cycle...and will be "weak".
True, a larger gap will cause a "hotter" spark...enhancing more complete combustion, but only to a point. If the mixture is overly weak, combustion will occur, though the "hot" spark conceivably will mask what should have been a mis-fire (fouled plug, in the extreme case).
More is not necessarily better...as a larger plug gap can lead to a mis-fire, if the ignition system isn't up to the task. Also, too large of a spark plug gap can cause unnecessary wear and tear on the rest of the ignition system...such as accelerated cap and rotor wear.
The manufacturers of spark plugs set the plug gap based on the design of the plug, not the specific engine requirements. NGK stated in my conversation with them that their plugs are designed to be gapped +/- .008" of their orginal pre-set gap. NGK does make wide gap plugs, that usually have the suffix -11. Typically these plugs are nominally gapped at around .035-.045".
HTH,
David