I must be doing it wrong too, I always adjust my engines when warmed to operating temps and while running. High end first then the low end then just fly? Once I have an engine set I don't bother twisting the needles again unless I change the prop size or we have a huge weather change. From summer to winter my high end needle only moves about 4 clicks and I almost never touch the low end. I do use a tach once in a while with a new engine. I have one gas engine I adjust with the engine off but just because the needles are facing the prop and there is only an inch of room between the prop and carb. All others I adjust while running. I tend to not over think things or make more work then needed.