Im updating this thread on my engine experiences.
one of my engines gets no spark after running fine for 4 hours, so Ive decided to go the CDI route, to put an end to the most finicky part of the plane.
Perhaps I should have used the $25 condensers after all, but Im not sure if the condenser is even at fault.
CDI just sounds like the best way to go in any case for smoother running at ALL speeds, and for a more powerfull spark that resists plug fouling.