That's a terrific reply and I thank you. I did go to that site and it's good also. The part that I want to follow-up on is the sleep position. From what you've said it makes sense that I stay off my back – period. Any tips on how? When I wake I am on my side and I don't know when I am on my back. My sciatica rolls me around a lot. I am a 79 year old male. Use pillows as wedges to prevent rolling over? Sleep propped up at 30 degrees? I think my hybrid mask is probably comfy enough. Is it worthwhile to invest in a pillow having one corner cut off so that the mask rests on nothing?