Hopefully this picture will help:
The changes in functionality are dramatic! I've been sleeping with this mask for over a year now, but the last few nights have literally been a dream.
I've already noticed the following changes:
1) I now realize I was really cinching down the upper straps to effectively "push" the hard plastic frame onto the cushion and thence onto my face to keep the cushion from unseating - this was where I had ended up over the course of the year but it happened so gradually I didn't realize it. Suddenly last week I woke up in the middle of the night and thought, "hey I bet I could back off on all this upper strap pressure" - did so and Presto! Better sealing mask, MUCH better comfort - and of course no leaks and no cushion coming undone. Just amazing.
2) I realize that there has always been a bit of background stress about the mask coming out; with the washing it in cold water, and then wiggling it in the seating, and falling asleep thinking "please god, let this thing not pop out tonight" - suddenly all of that has gone away. Again, because it had been happening gradually I didn't realize how much mental process and stress went into it. But now its gone away - just joy.
3) Now with the mask seal, I've moved the strap back towards more the top of my head and the "proper" position, which has also backed off pressure on the nose.
4) My large leak and AHI numbers have come down already - and I'm only 5 days into this. Excited to see where they will end up.
Anyway, just wanted to thank everyone for thinking about this, for the original floss suggestion, for the rubber band pictures, for the new improved rigged head gear and for all the great thought you guys have put into this. Life changing!
Seems that Respironics version of the mask might also be worth checking out - but in the mean time thanks a million for the great ideas here.