Bend slowly, & from the side of the electrode. Don't tap it on anything.
Measure, bend, re-measure. Don't bend it with the feeler gauge in the gap.
I always thought that a larger gap created a hotter spark. For ex. on really cold days, we used to pull the coil wire off the top of the cap, & position the wire so that it was an inch or so from where it should be. Most times, @ below freezing this would help an engine get that extra kick it needed to start. Once it was warmed up a bit, the wire could be replaced in the cap. After turning it off, of course.
With the old points & condensor system, we'd go 2 heat ranges cooler, with a gap of .045, as opposed to the standard .035. This, apparently, creates a more even burn across the top of the piston.
Both my trucks are fussy about plugs. Some plugs they just don't like. If they're wrong, it kills my mileage & the quality of the way the engines idle & perform through the rpm range. Some created a stumble off idle, & others would drop off in performance farther up the rpm, or when being worked under load. Some caused an occasional cough, or miss when at a steady rpm.
They seem to prefer the Rapid Fires.