The OS-F is a "four-stroke" plug, right? Just asking. Perhaps that's why it works better.. has to be hot to endure the latency between the cycles. Yeah, it seems that I use the F plug a lot too.

There is no magic bullet here.. just a lot or experimentation that we have to do to find out what works for each of us under our flying conditions. What works for one may not work for another. We try to pass on as much good and useful information that we have under our particular circumstances... altitude, weather, temperature, flying style... and all that stuff.

CGr.