My zwave stick arrived today and I finally have the sniffer app working - but the app has really complex options and screens so I haven’t yet figure out how to inspect for ghost nodes.
[EDIT] answered my own question by searching for zniffer on this forum and found an amazing thread with step by step directions here:
And on Inovelli I tried updating one and bricked it so I’m a little gun shy to try the others. Maybe later after my ghost hunt.
And finally, my new C7 hub arrived today and based on the advice here I will definitely build out my mesh manually. That will take time and I plan to do it gradually so finding the ghosts is still important. I don’t think the method of checking laggy devices will help since pretty much all of them are misbehaving from time to time.