I know this won't be sfair approved, but I used to have an old Suzuki 550 inline four banger. When started, it frequently wouldn't fire on one or two of its cylinders. To get a spark "hot" enough to fire the plugs, I would partially pull the plug wire up on the plug's insulator about a half-inch or so, so that the spark had to make the jump from the wire terminal to the spark plug's terminal. With the engine running, I could pull up on the wire until I could hear the spark snapping inside the boot. The cylinder would immediately "catch" using this method. The spark at the plug's business end was then hot enough to fire the cylinder. I'd then reseat the wire and be on my way. I think maybe a larger gap on the plugs would accomplish the same thing.
I never knew if the added gap caused the spark to actually be "hotter", as in more voltage produced, but this method certainly worked!
Ron in Cincinnati
Wish I didn't know now what I didn't know then.