just what do you think these very accurately set air/fuel mixtures are at idle conditions? And ahh here comes the stinger, what do you define as "way overgeared", what is "lugging the engine too low? Not a very well chosen rear gear if the automatic has to geardown to negotiate a hill at 70 mph (Pikes Peak perhaps).
But the nugget to salvage from all this and the principle purpose of the thread is captured in your sentence about..."idle circuit has an important role at (low-my opinion) cruising speeds,light throttle", as no one has spoken this fact on this bulletin board pror to now.
To me overgeared with a too low numerically ratio will keep you under the grip of the "very accurately' adjusted idle circuit far too long.
