An experienced aero-engine engineer, who flies his own Rotax 912-powered aircraft, just made this comment to me:
In the "Shut down" checks, I personally would add throttle to idle immediately before the switching off......I find the engine shut off is much softer if the throttle is brought to absolute idle, then 1 mag switch turned off, followed 1 second later by the second switch. Note, I am not advocating letting the engine actually idle below 2200 for any real period of time.
I think that was mentioned previously on this thread.
Many thanks to all previous - much appreciated.