As we all do and so we should
BTW, I agree with everything you said too. Yes, idle and transition play a part in choosing a plug even if it means losing a little on the top end. The best site I've found about plugs and the affect on the engine for different heat ranges is at http://www.modeltechnics.com/glowplug/firepower.html where they take into account things like idle, transition, max revs before selecting the best plug for that engine/prop/fuel/compression. But even from their results it can be seen that most plugs from the hottest to coldest give acceptable results for a sports flyer.