Thanks to all who responded for the good suggestions. Mike, I don't do too much breathing through my nose during the day because I have narrowed nostrils which actually require surgery, but I don't feel like salami right now. The reason I can use a nasal mask at all is that the pressure splints my nostrils wide enough that I can breathe enough through one nostril to manage.
Yes Lori, I am still using the Aura. I like it very much for the wonderful headgear which gives me so much freedom of movement. The Swift cushions were a bit more to my taste, however, but only a bit.
I think the whole thing can be whittled down to, "just do it". I too have found the sweet spot where my tongue needs to be to close the mouth off. It's just getting it to stay there. I have a theory that if I would take off the tape and chinstrap it would take about a week of litte or diminished sleep before I would master this. It's just that I am not confronting the upcoming punishment.