RE: Spark plug gap
Which brought you right back to having to experiment....
The RC Exl systems fall pretty much into a high average voltage range. They do a real good job for our applications but there's no reaso to make them work harder than they have to. Using the correct input voltage and a reasonable gap keeps them happy for a long time. As noted in the NGK post, wide gaps require more energy to bridge, and unless the ignition has the ability to deliver large energy amounts on a high frequency basis you won't maximize the performance of the system. The coils have to receive the energy needed to bridge the gap, and the more energy required the harder it becomes for the coil to be recharged in the amout of time allotted. After a point the coil is delivering less energy with most all ignitions but the user can easily make the situation worse with excessive gaps. Better plugs can do a better job but they require even more energy... Better ignitions cost a heck of a lot more as well so people have to balance all the related factors.
What we have for what we do isn't broke so there's no need to fix it.