Yes a 912, so you know what the Bings look like anyway. Just the two idle screws are wound back far enough to ensure that they can never be contacted by the throttle arms. The springs are attached to the arms to pull them towards fully open, if the linkage should fail. My modified penny washer "cam" is at the rear of cockpit throttle lever travel, to act as an idle stop. The aircraft designer indicates in the build instructions that the idle stop should be in the cockpit. Other builders will have devised their own means of adjusting idle speed, perhaps at the carburettors by adjusting throttle cables and having only a fixed stop in the cockpit. My way might be easier; I don't know for sure.